Code samples for my book on Querying data with Transact-SQL (MCSA 70-761), chapter 2

USE WideWorldImporters;

/* Query data by using subqueries and APPLY */

-- 001
-- simple subquery
SELECT	o.*
FROM	(SELECT * FROM Sales.Orders) o

-- 002
SELECT	*
FROM	[Application].[People]
WHERE	PreferredName IN (	SELECT	CustomerName
				FROM	sales.Customers )

-- 003
USE TestDB;

SELECT	*
	,(SELECT AVG(salary) FROM dbo.Employees) AS average_salary
FROM	dbo.Employees

-- 004
SELECT	*
FROM	dbo.Employees
WHERE	Salary > (SELECT AVG(salary) FROM dbo.Employees)

-- 005
-- correlated subquery
SELECT	*
FROM	dbo.Employees e1
WHERE	Salary > (	SELECT	AVG(salary) 
					FROM	Employees e2 
					WHERE	e1.department = e2.department)

-- 006
SELECT	*
FROM	dbo.Employees e1
	INNER JOIN (SELECT	AVG(salary) AS avg_salary, department
		    FROM	dbo.employees
		    GROUP BY department) e2 ON e1.Department = e2.Department
WHERE	salary > e2.avg_salary

-- 007
SELECT	*
	, (SELECT AVG(salary) FROM Employees e2 WHERE e1.department = e2.Department)
FROM	Employees e1
WHERE	Salary > (	SELECT	AVG(salary) 
			FROM	Employees e2 
			WHERE	e1.Department = e2.department)

-- 008
SELECT	*
FROM	Departments d
WHERE (	SELECT	count (*)
	FROM	Employees e 
	WHERE	e.Department = d.Department) > 2 

-- 009
ALTER TABLE Departments ADD Location varchar(100) DEFAULT 'Houston' WITH VALUES;
GO
UPDATE Departments
SET 	Location = 'New York'
WHERE 	Department = 'Management'


/* Evaluate performance differences between table joins and correlated subqueries based on provided data and query plans */

-- 010
SELECT	*
INTO	Customers_copy
FROM	WideWorldImporters.sales.Customers

SELECT	*
INTO	orders_copy
FROM	WideWorldImporters.sales.orders

-- 011
-- join faster
SELECT	c.CustomerName, o.lastorderdate, o.NumberOfOrders
FROM	(SELECT customerID, max(orderdate) AS LastOrderDate, count(*) AS NumberOfOrders
	FROM	orders_copy
	GROUP BY CustomerID) o
	INNER JOIN Customers_copy c on c.CustomerID = o.customerId

SELECT CustomerName
	,(	SELECT MAX(orderdate) 
		FROM orders_copy o 
		WHERE c.customerId = o.customerID ) AS LastOrderDate
	,(	SELECT COUNT(*) 
		FROM orders_copy o 
		WHERE c.customerId = o.customerID )AS NumberOfOrders
FROM	Customers_copy c

-- 012
-- correlated subquery faster
SELECT	*
FROM	Customers_copy c
	LEFT OUTER JOIN orders_copy o on c.CustomerID = o.CustomerID
WHERE	o.CustomerID IS NULL

SELECT	*
FROM	Customers_copy c
WHERE NOT EXISTS (	SELECT	* 
			FROM	orders_copy o 
			WHERE	c.CustomerID = o.CustomerID)

/* Distinguish between the use of CROSS APPLY and OUTER APPLY */

-- 013
SELECT	* 
FROM	Departments d
	CROSS APPLY 
	(	SELECT * 
FROM 	Employees e 
		WHERE 	e.Department = d.Department) table_alias

SELECT	* 
FROM	Departments d
	INNER JOIN Employees e ON d.Department = e.Department

-- 014
INSERT Departments VALUES ('Research', 'Eindhoven')

SELECT	* 
FROM	Departments d
	OUTER APPLY 
	(	SELECT * 
FROM 	Employees e 
		WHERE 	e.Department = d.Department) table_alias

SELECT	* 
FROM	Departments d
	LEFT OUTER JOIN Employees e ON d.Department = e.Department

-- 015
CREATE FUNCTION dbo.fn_GetListOfEmployees(@Department AS varchar(100))  
RETURNS TABLE 
AS 
RETURN 
   ( 
   SELECT	FirstName + ' ' + LastName AS FullName, Salary
   FROM	Employees e 
   WHERE	e.Department = @Department 
   ) 

-- 016
SELECT	*
FROM	dbo.fn_GetListOfEmployees('Engineering')

-- 017
SELECT	*
FROM	Departments d
	CROSS APPLY dbo.fn_GetListOfEmployees(d.Department)

-- 018
SELECT	session_id, DB_NAME(database_id) AS [database], start_time
		, open_transaction_count,  [text] AS [Query] 
FROM	sys.dm_exec_requests r 
	CROSS APPLY sys.dm_exec_sql_text(r.plan_handle) s 
WHERE	session_id > 50           -- Exclude system spids
ORDER BY session_id;

/* Query data by using table expressions */


--Identify basic components of table expressions
SELECT	o.*
FROM	(SELECT * FROM Sales.Orders) o

-- common table expression
WITH o 
AS (	SELECT * 
	FROM Sales.Orders)
SELECT	*
FROM	o


SELECT	*
FROM	dbo.Employees e1
WHERE	Salary > (	SELECT	AVG(salary) 
					FROM	Employees e2 
					WHERE	e1.Department = e2.department);

-- readability example
SELECT	c.CustomerName, o.lastorderdate, o.NumberOfOrders
FROM	(SELECT customerID, max(orderdate) AS LastOrderDate, count(*) AS NumberOfOrders
		FROM	orders_copy
		GROUP BY CustomerID) o
		INNER JOIN Customers_copy c on c.CustomerID = o.customerId;


WITH o AS (
	SELECT customerID, max(orderdate) AS LastOrderDate, count(*) AS NumberOfOrders
	FROM	orders_copy
	GROUP BY CustomerID)
SELECT	c.CustomerName, o.lastorderdate, o.NumberOfOrders
FROM	o
		INNER JOIN Customers_copy c on c.CustomerID = o.customerId

--Construct recursive table expressions to meet business requirements


-- Recursive cte, top to bottom:
ALTER TABLE Employees ADD ManagerID tinyint NULL;
GO
INSERT Employees (FirstName,LastName, Salary, Department, ManagerID)
VALUES ('Harriet', 'Hughes', 1800.00,'Sales',7);
INSERT Employees (FirstName,LastName, Salary, Department, ManagerID)
VALUES ('Ronnie', 'Robertson', 1800.00,'Engineering',7);

UPDATE	Employees 
SET		ManagerID = (SELECT EmployeeID FROM Employees WHERE FirstName = 'Harriet')
WHERE	Department = 'Sales' AND FirstName <> 'Harriet'

UPDATE	Employees 
SET		ManagerID = (SELECT EmployeeID FROM Employees WHERE FirstName = 'Ronnie')
WHERE	Department = 'Engineering' AND FirstName <> 'Ronnie'

ALTER TABLE Employees ADD CONSTRAINT PK_EmployeeID PRIMARY KEY (EmployeeID)

ALTER TABLE Employees ADD CONSTRAINT FK_EmployeeID FOREIGN KEY (ManagerID) REFERENCES Employees(EmployeeID)
GO

WITH Employee_CTE AS (
	SELECT	EmployeeID,  ManagerID, Firstname + ' ' + LastName AS Name, 0 as Level
	FROM	Employees
	WHERE	ManagerID IS NULL
	UNION ALL
	SELECT	e1.EmployeeID, e1.ManagerID, Firstname + ' ' + LastName, e2.level + 1
	FROM	Employees e1
			INNER JOIN Employee_CTE e2 ON e2.EmployeeID = e1.ManagerID
)
SELECT	Name,  Level
FROM	Employee_CTE
ORDER BY  Level, Name

-- Recursive cte, bottom to top:
WITH Employee_CTE AS (
	SELECT	EmployeeID,  ManagerID, Firstname + ' ' + LastName AS Name, 0 as Level
	FROM	Employees
	WHERE	EmployeeID NOT IN (SELECT ManagerID FROM Employees WHERE ManagerID IS NOT NULL)
	UNION ALL
	SELECT	e1.EmployeeID, e1.ManagerID, Firstname + ' ' + LastName, e2.level + 1
	FROM	Employees e1
			INNER JOIN Employee_CTE e2 ON e1.EmployeeID = e2.ManagerID
)
SELECT	DISTINCT Name,  Level
FROM	Employee_CTE
ORDER BY  Level, Name


-- Recursive CTE, final example
WITH Employee_CTE AS (
	SELECT	EmployeeID, ManagerID, 0 as Level
	FROM	Employees
	WHERE	EmployeeID NOT IN (SELECT ManagerID FROM Employees WHERE ManagerID IS NOT NULL)
	UNION ALL
	SELECT	e1.EmployeeID, e1.ManagerID, e2.level + 1
	FROM	Employees e1
			INNER JOIN Employee_CTE e2 ON e1.EmployeeID = e2.ManagerID
)
,
Distinct_CTE AS (
	SELECT DISTINCT EmployeeID,  ManagerID, Level
	FROM Employee_CTE)
SELECT	e2.FirstName + ' ' + e2.LastName AS Name, e3.FirstName + ' ' + e3.LastName AS Manager, Level
FROM	Distinct_CTE e1
		INNER JOIN Employees e2 ON e1.employeeID = e2.EmployeeID
		LEFT OUTER JOIN Employees e3 ON e1.ManagerID = e3.EmployeeID
ORDER BY Level, Name


--multiple CTEs
WITH Employee_CTE AS (
	SELECT	EmployeeID, ManagerID, 0 as Level
	FROM	Employees
	WHERE	EmployeeID NOT IN (	SELECT ManagerID 
FROM 	Employees 
WHERE 	ManagerID IS NOT NULL)
	UNION ALL
	SELECT	e1.EmployeeID, e1.ManagerID, e2.level + 1
	FROM	Employees e1
		INNER JOIN Employee_CTE e2 ON e1.EmployeeID = e2.ManagerID
)
,
Distinct_CTE AS (
	SELECT DISTINCT EmployeeID,  ManagerID, Level
	FROM Employee_CTE)
SELECT	e2.FirstName + ' ' + e2.LastName AS Name
, e3.FirstName + ' ' + e3.LastName AS Manager, Level
FROM	Distinct_CTE e1
	INNER JOIN Employees e2 ON e1.employeeID = e2.EmployeeID
	LEFT OUTER JOIN Employees e3 ON e1.ManagerID = e3.EmployeeID
ORDER BY Level, Name

--Temporary table
SELECT	*
INTO	#tmp_Employees
FROM	Employees

SELECT	*
FROM	#tmp_Employees

ALTER TABLE #tmp_Employees ADD Description varchar(100) NULL

DROP TABLE #tmp_Employees

SELECT	*
FROM	tempdb.sys.objects
WHERE	name LIKE '#tmp_Employees%'

--Table variables
DECLARE @Employees TABLE (
	[EmployeeID] [tinyint] NOT NULL,
	[FirstName] [varchar](100) NULL,
	[LastName] [varchar](50) NULL,
	[Address] [varchar](100) NULL,
	[Salary] [decimal](18, 2) NULL,
	[Department] [varchar](100) NULL,
	[Employee_Number] [int] NULL,
	[ManagerID] [tinyint] NULL)

INSERT INTO @Employees
SELECT	*
FROM	Employees

--Group and pivot data by using queries
--Construct complex GROUP BY clauses using GROUPING SETS, and CUBE

DROP TABLE IF EXISTS UFO_Sightings;
GO
CREATE TABLE UFO_Sightings (
CountryID tinyint
, Country varchar(50)
, State varchar(50)
, City varchar(50)
, UFO_Sightings int );

INSERT INTO UFO_Sightings VALUES (1, 'Germany', NULL, 'Berlin', 1)
INSERT INTO UFO_Sightings VALUES (1, 'Germany', NULL, 'Frankfurt', 2)
INSERT INTO UFO_Sightings VALUES (1, 'Germany', NULL, 'Frankfurt', 3)
INSERT INTO UFO_Sightings VALUES (2, 'United States', 'Texas', 'Houston', 1)
INSERT INTO UFO_Sightings VALUES (2, 'United States', 'Texas', 'Paris', 2)
INSERT INTO UFO_Sightings VALUES (2, 'United States', 'Nevada', NULL, 300)
INSERT INTO UFO_Sightings VALUES (3, 'France', NULL, 'Paris', 1);

SELECT	*
FROM	UFO_Sightings

SELECT	Country, SUM(UFO_Sightings)
FROM	UFO_Sightings
GROUP BY Country

SELECT	SUM(UFO_Sightings)
FROM	UFO_Sightings

SELECT	SUM(UFO_Sightings)
FROM	UFO_Sightings
GROUP BY ()

SELECT	Country, City, SUM(UFO_Sightings)
FROM	UFO_Sightings
GROUP BY Country, City
ORDER BY Country, City;

SELECT	Country, SUM(UFO_Sightings)
FROM	UFO_Sightings
WHERE	City <> 'Paris'
GROUP BY Country

SELECT	Country, SUM(UFO_Sightings)
FROM	UFO_Sightings
WHERE	ISNULL(City,'') <> 'Paris'
GROUP BY Country

SELECT	CountryID, Country, SUM(UFO_Sightings)
FROM	UFO_Sightings
GROUP BY Country

SELECT	Country, SUM(UFO_Sightings) AS TotalNumberOfSightings
FROM	UFO_Sightings
GROUP BY Country
HAVING	SUM(UFO_Sightings) > 100;

WITH ufo AS (
	SELECT	Country, SUM(UFO_Sightings) AS TotalNumberOfSightings
	FROM	UFO_Sightings
	GROUP BY Country)
SELECT	*
FROM	ufo
WHERE	TotalNumberOfSightings > 100

INSERT INTO UFO_Sightings VALUES (4, 'Belgium', NULL, 'Brussels', NULL);

SELECT Country, COUNT(UFO_Sightings) AS Count_1, COUNT(*) AS Count_2
FROM	UFO_Sightings
GROUP BY Country

SELECT Country, State, SUM(UFO_Sightings) AS TotalUFO_Sightings
FROM	UFO_Sightings
GROUP BY Country, State

--complex GROUP BY logic
SELECT Country, City, SUM(UFO_Sightings) AS TotalUFO_Sightings
FROM UFO_Sightings
GROUP BY Country, City
ORDER BY Country, City

SELECT Country, City, SUM(UFO_Sightings) AS TotalUFO_Sightings
FROM UFO_Sightings
GROUP BY ROLLUP (Country, City);

SELECT Country, NULL AS City, SUM(UFO_Sightings) AS TotalUFO_Sightings
FROM 	UFO_Sightings
GROUP BY Country 
UNION ALL
SELECT Country, City, SUM(UFO_Sightings) AS TotalUFO_Sightings
FROM 	UFO_Sightings
GROUP BY Country, City 
UNION ALL
SELECT NULL, NULL, SUM(UFO_Sightings) AS TotalUFO_Sightings
FROM 	UFO_Sightings
GROUP BY ()

GROUP BY Country, City WITH ROLLUP;

SELECT	Country, GROUPING(Country) AS Is_result_of_grouping_countries
	, State, GROUPING(State) AS Is_result_of_grouping_cities
FROM UFO_Sightings
GROUP BY Country, State WITH ROLLUP

SELECT	CASE 
		WHEN GROUPING(Country) = 1 THEN 'Grand Total' 
		WHEN GROUPING(State) = 1 THEN 'Total for ' + Country 
		ELSE ''
	END	AS Totals
	, Country
	, State
	,SUM(UFO_Sightings) AS TotalUFO_Sightings
FROM	UFO_Sightings
GROUP BY Country, State WITH ROLLUP

SELECT Country, State, GROUPING_ID(Country, State )
FROM UFO_Sightings
GROUP BY Country, State WITH ROLLUP

ALTER TABLE UFO_Sightings ADD Continent varchar(100) NULL

GO --required batch separator, otherwise query will fail on missing column

UPDATE UFO_Sightings 
SET 	Continent = 'Europe' 
WHERE 	Country IN ('Germany', 'France', 'Belgium')

UPDATE UFO_Sightings 
SET 	Continent = 'North America' 
WHERE 	Country IN ('United States')

SELECT	Continent
	, Country
	, State
	, GROUPING_ID(Continent, Country, State )
	, GROUPING(Continent) * 4 + GROUPING(Country) * 2 +  GROUPING(State)
FROM	UFO_Sightings
GROUP BY Continent, Country, State WITH ROLLUP

SELECT Country, City, SUM(UFO_Sightings) AS TotalUFO_Sightings
FROM UFO_Sightings
GROUP BY CUBE (Country, City)
ORDER BY 1, 2;

-- CUBE dissected: A & NULL, NULL & B, A & B, NULL & NULL
SELECT Country, NULL AS City, SUM(UFO_Sightings) AS TotalUFO_Sightings
FROM UFO_Sightings
GROUP BY (Country)
UNION ALL
SELECT NULL, City, SUM(UFO_Sightings) AS TotalUFO_Sightings
FROM UFO_Sightings
GROUP BY ( City)
UNION ALL
SELECT Country, City, SUM(UFO_Sightings) AS TotalUFO_Sightings
FROM UFO_Sightings
GROUP BY Country, City
UNION ALL
SELECT NULL, NULL, SUM(UFO_Sightings) AS TotalUFO_Sightings
FROM UFO_Sightings
ORDER BY 1, 2

SELECT Continent
, Country
, City
, SUM(UFO_Sightings) AS TotalUFO_Sightings
, GROUPING_ID(Continent,Country, City)
FROM UFO_Sightings
GROUP BY CUBE (Continent, Country, City)
ORDER BY 5;

SELECT	Country, City, SUM(UFO_Sightings) AS TotalUFO_Sightings
FROM	UFO_Sightings
GROUP BY GROUPING SETS ( Country, City)

SELECT	Country, NULL, SUM(UFO_Sightings) AS TotalUFO_Sightings
FROM	UFO_Sightings
GROUP BY  Country
UNION ALL
SELECT	NULL, City, SUM(UFO_Sightings) AS TotalUFO_Sightings
FROM	UFO_Sightings
GROUP BY  City

SELECT	Country, City, SUM(UFO_Sightings) AS TotalUFO_Sightings
FROM	UFO_Sightings
GROUP BY GROUPING SETS ( Country, City, ())

--Use windowing functions to group and rank the results of a query
DROP TABLE IF EXISTS Runner_info

CREATE TABLE Runner_info (
	Runner		varchar(50)
	,Nickname	varchar(50)
	,Race		varchar(50)
	,Race_date	date
	,Distance	decimal(8,3)
	,Finish_time	time)
GO
INSERT Runner_info VALUES ('Jack', 'The Flash', 'New York marathon', '2016-11-06', 42.195, '2:53:00')
INSERT Runner_info VALUES ('Jack', 'The Flash', 'New York marathon', '2017-11-05', 42.195, '2:55:00')
INSERT Runner_info VALUES ('Jack', 'The Flash', 'Berlin marathon', '2016-09-25', 42.195, '2:45:00')

INSERT Runner_info VALUES ('Juan Gonzalez', 'Speedy', 'New York marathon', '2016-11-06', 42.195, '3:22:00')
INSERT Runner_info VALUES ('Juan Gonzalez', 'Speedy', 'New York marathon', '2017-11-05', 42.195, '3:18:30')

INSERT Runner_info VALUES ('Rudy', 'Roadrunner', 'New York marathon', '2016-11-06', 42.195, '4:01:00')
INSERT Runner_info VALUES ('Rudy', 'Roadrunner', 'New York marathon', '2017-11-05', 42.195, '4:05:30')
INSERT Runner_info VALUES ('Rudy', 'Roadrunner', 'Berlin marathon', '2016-09-25', 42.195, '3:59:59')
INSERT Runner_info VALUES ('Rudy', 'Roadrunner', 'Berlin marathon', '2017-09-24', 42.195, '4:13:00')
INSERT Runner_info VALUES ('Rudy', 'Roadrunner', 'Rotterdam half marathon', '2017-04-07', 21.1, '1:52')

SELECT	*
FROM	Runner_info	

SELECT	*
	,COUNT(*) OVER () AS Nr_of_races_total
FROM	Runner_info	

SELECT	*
	,COUNT(*) OVER () AS Nr_of_races_total
	,COUNT(*) OVER (PARTITION BY Runner) AS Nr_of_races_per_runner
FROM	Runner_info	

SELECT	*
	,COUNT(*) OVER (PARTITION BY Runner) AS Nr_of_races_per_runner
FROM	Runner_info	
WHERE	Distance = 42.195

SELECT	Runner
	,Race
	,Race_date
	,Finish_time
	,MIN(Finish_time) OVER (PARTITION BY Runner, Race)  AS Race_PR
	,DATEDIFF(mi,MIN(Finish_time) OVER (PARTITION BY Runner, Race), Finish_time)  AS Slower_than_PR
FROM	Runner_info	

OVER (	PARTITION BY column
	ORDER BY column
	ROWS BETWEEN … AND …)

SELECT	Runner, Race, Race_date, distance
	,SUM(distance) OVER (PARTITION BY Runner 
				ORDER BY Race_date
				ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) 
AS Cumulative_distance
FROM	Runner_info	
WHERE	Runner = 'Rudy'
ORDER BY Runner, Race_date

SELECT	Runner, Race, Race_date, distance
	,AVG(distance) OVER (PARTITION BY Runner 
				ORDER BY Race_date
				ROWS BETWEEN 2 PRECEDING AND 2 FOLLOWING) 
AS Running_average
FROM	Runner_info	
WHERE	Runner = 'Rudy'
ORDER BY Runner, Race_date

INSERT Runner_info VALUES ('Rudy', 'Roadrunner', 'Ran home', '2017-11-05', 10, '1:10')

SELECT	Runner, Race, Race_date, distance
	,SUM(distance) OVER (PARTITION BY Runner 
				ORDER BY Race_date
				ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) 
AS Cumulative_distance
FROM	Runner_info	
WHERE	Runner = 'Rudy'
ORDER BY Runner, Race_date

SELECT	Runner, Race, Race_date, distance
	,SUM(distance) OVER (PARTITION BY Runner 
				ORDER BY Race_date
				RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) 
AS Cumulative_distance
FROM	Runner_info	
WHERE	Runner = 'Rudy'
ORDER BY Runner, Race_date

--Ranking window functions
SELECT	Runner, Race, Race_date, Finish_time
	,ROW_NUMBER() OVER (ORDER BY Finish_time) AS rownumber
	,RANK() OVER (ORDER BY Finish_time) AS rank
	,DENSE_RANK() OVER (ORDER BY Finish_time) AS denserank
	,NTILE(5) OVER (ORDER BY Finish_time) AS ntile
FROM	Runner_info
WHERE	Distance = 42.195
ORDER BY rownumber

INSERT Runner_info VALUES ('Fred', 'The Shadow', 'New York marathon', '2016-11-06', 42.195, '2:53:00')

--Analytic window functions
SELECT	FirstName, LastName, Department, Salary
FROM	dbo.Employees

SELECT	FirstName, LastName, Department, Salary
	,LAG(Salary) OVER (ORDER BY Salary) as lag
	,LEAD(Salary) OVER (ORDER BY Salary) as lead
FROM	Employees

SELECT	FirstName, LastName, Department, Salary
	,LAG(Salary) OVER (ORDER BY Salary) as lag
	,LEAD(Salary) OVER (ORDER BY Salary) as lead
FROM	Employees
ORDER BY LastName

SELECT	FirstName, LastName, Department, Salary
	,LAG(Salary, 2) OVER (ORDER BY Salary) as lag
	,LEAD(Salary, 2) OVER (ORDER BY Salary) as lead
FROM   Employees

SELECT	FirstName, LastName, Department, Salary
	,LAG(Salary, 2, 'not applicable') OVER (ORDER BY Salary) as lag
	,LEAD(Salary, 2, 'not applicable') OVER (ORDER BY Salary) as lead
FROM	Employees

SELECT	FirstName, LastName, Department, Salary
	,LAG(Salary) OVER (PARTITION BY Department ORDER BY Salary) as lag
	,LEAD(Salary) OVER (PARTITION BY Department ORDER BY Salary) as lead
FROM   Employees
ORDER BY Department

SELECT	FirstName, LastName, Department, Salary
	,FIRST_VALUE(FirstName + ' ' +  LastName) 
OVER (	PARTITION BY Department 
ORDER BY Salary) 
as Least_earning_employee
	,LAST_VALUE(FirstName + ' ' +  LastName) 
OVER (	PARTITION BY Department
ORDER BY Salary
			RANGE BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) 
as Most_earning_employee
FROM   Employees
ORDER BY Department, Salary

SELECT	FirstName, LastName, Department, Salary
	,CUME_DIST() OVER (ORDER BY Salary) as cumulative_distance
	,CUME_DIST() OVER (ORDER BY Salary) * COUNT(*) OVER () as equal_or_less
FROM   Employees
ORDER BY Salary

INSERT dbo.Employees (FirstName, LastName, Salary, Department) 
VALUES ('James', 'Peterson', 900, 'Engineering')

SELECT	FirstName, LastName, Department, Salary
	,PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BY Salary) OVER () as median_salary
	,PERCENTILE_DISC(0.5) WITHIN GROUP (ORDER BY Salary) OVER () as median_salary
FROM   Employees
ORDER BY Salary

SELECT	FirstName, LastName, Department, Salary
	,PERCENT_RANK() OVER (ORDER BY Salary) as fraction_lower_than_this
	,CAST(PERCENT_RANK() OVER (ORDER BY Salary) * 100 AS dec(5,1)) 
as percentage_lower_than_this
FROM   Employees
ORDER BY Salary

--Construct PIVOT and UNPIVOT statements to return desired results based on supplied data
SELECT	CustomerName, si.StockItemName, sum(quantity) as quantity
FROM	sales.Customers c
	INNER JOIN sales.Orders o on c.CustomerID = o.CustomerID
	INNER JOIN sales.OrderLines ol on o.OrderID = ol.OrderID
	INNER JOIN Warehouse.StockItems si on ol.StockItemID = si.StockItemID
WHERE	c.CustomerID IN (	SELECT	TOP 5 CustomerID 
				FROM	Sales.Orders 
				GROUP BY CustomerID
				ORDER BY COUNT(*))
	AND si.StockItemID IN (	SELECT TOP 5 StockItemID 
					FROM Sales.Orderlines 
					GROUP BY StockItemID 
					ORDER BY COUNT(*))
GROUP BY CustomerName, si.StockItemName
ORDER BY CustomerName, si.StockItemName

--PIVOT and UNPIVOT
WITH cte AS(
	SELECT	CustomerName, si.StockItemName, quantity
	FROM	sales.Customers c
		INNER JOIN sales.Orders o on c.CustomerID = o.CustomerID
		INNER JOIN sales.OrderLines ol on o.OrderID = ol.OrderID
		INNER JOIN Warehouse.StockItems si on ol.StockItemID = si.StockItemID
	WHERE	si.StockItemID IN (	SELECT TOP 5 StockItemID 
					FROM Sales.Orderlines 
					GROUP BY StockItemID 
					ORDER BY COUNT(*))
)
SELECT	 *
FROM	cte
	PIVOT (SUM(quantity)
		FOR CustomerName IN ([Anand Mudaliyar],[Jibek Juniskyzy]
,[Agrita Abele],[Kalyani Benjaree],[Jaroslav Fisar])) 
		AS SalesQuantity

USE TestDB
GO
DROP TABLE IF EXISTS Sales;
GO
CREATE TABLE Sales(
	Customer	varchar(50)
	, Product	varchar(50)
	, Quantity	int)

INSERT INTO Sales(Customer, Product, Quantity)
VALUES('John','Apples',4)
,('John','Bananas',7)
,('John','Cantaloupe',1)
,('John','Apples',5)
,('John','Beer',6)
,('Bill','Cantaloupe',3)
,('Bill','Beer',24)
,('Diana','Apples',6)
,('Diana','Bananas',5)
,('Diana','Cantaloupe',2)

SELECT	*
FROM	Sales

-- Pivot customers
SELECT	Product, Bill, John, Diana
FROM	Sales
	PIVOT (SUM(Quantity) 
		FOR Customer IN (Bill, John, Diana)) AS some_alias
ORDER BY Product

-- Pivot product
SELECT	Customer, Apples, Bananas, Cantaloupe , Beer, [Magic mushrooms]
FROM	Sales
	PIVOT (SUM(Quantity) 
FOR Product IN (Apples, Bananas, Cantaloupe , Beer, [Magic mushrooms])) AS some_alias
ORDER BY Customer

-- adding a column
ALTER TABLE Sales ADD CustomerID int NULL
GO
UPDATE Sales SET CustomerID = 1 WHERE Customer = 'Bill'
UPDATE Sales SET CustomerID = 2 WHERE Customer = 'John'
UPDATE Sales SET CustomerID = 3 WHERE Customer = 'Diana'

SELECT	Product, Bill, John, Diana
FROM	Sales
	PIVOT (SUM(Quantity) 
		FOR Customer IN (Bill, John, Diana)) AS some_alias
ORDER BY Product

ALTER TABLE Sales DROP CustomerID

SELECT	Customer, Apples, Bananas, Cantaloupe , Beer, [Magic mushrooms]
INTO	Pivoted_sales_table
FROM	Sales
	PIVOT (SUM(Quantity) 
FOR Product IN (Apples, Bananas, Cantaloupe , Beer, [Magic mushrooms])) AS some_alias
ORDER BY Customer

SELECT	*
FROM	Pivoted_sales_table

SELECT	Customer, Product, Quantity
FROM	Pivoted_sales_table
	UNPIVOT(	Quantity FOR 
			Product IN (	Apples, Bananas, Cantaloupe 
, Beer, [Magic mushrooms])
) AS some_alias


--Determine the impact of NULL values in PIVOT and UNPIVOT queries
--Count(*) not allowed
SELECT	Product, Bill, John, Diana
FROM	Sales
	PIVOT (COUNT(Quantity) 
		FOR Customer IN (Bill, John, Diana)) AS some_alias
ORDER BY Product

SELECT	Customer, Apples, Bananas, Cantaloupe , Beer, [Magic mushrooms]
FROM	Sales
	PIVOT (MIN(Quantity), MAX(Quantity)
FOR Product IN (Apples, Bananas, Cantaloupe , Beer, [Magic mushrooms])) AS some_alias
ORDER BY Customer


USE TestDB
GO
DROP TABLE IF EXISTS Sales;
DROP TABLE IF EXISTS Pivoted_sales_table;

--Query temporal data and non-relational data

--Query historic data by using temporal tables
USE WideWorldImporters
GO

SELECT	CountryName, LatestRecordedPopulation
FROM	Application.Countries

SELECT	CountryName, LatestRecordedPopulation
FROM	Application.Countries
FOR SYSTEM_TIME AS OF '2013-01-01 00:00:00.0000000'
WHERE	CountryName = 'Australia'

SELECT	CountryName, LatestRecordedPopulation, ValidFrom, ValidTo
FROM	Application.Countries
FOR SYSTEM_TIME ALL
WHERE	CountryName = 'Australia'

SELECT CountryName, LatestRecordedPopulation, ValidFrom, ValidTo
FROM	Application.Countries
FOR	SYSTEM_TIME 	FROM '2013-07-01 16:00:00.0000000' 
TO '2015-07-01 16:00:00.0000000'
WHERE	CountryName = 'Australia'

SELECT	CountryName, LatestRecordedPopulation, ValidFrom, ValidTo
FROM	Application.Countries
FOR	SYSTEM_TIME 	BETWEEN '2013-07-01 16:00:00.0000000' 
AND '2015-07-01 16:00:00.0000000'
WHERE	CountryName = 'Australia'

DECLARE @now datetime2 = SYSDATETIME()
SELECT	CountryName, LatestRecordedPopulation, ValidFrom, ValidTo
FROM	Application.Countries
FOR	SYSTEM_TIME CONTAINED IN ('2013-07-01 15:00:00.0000000', @now)
WHERE	CountryName = 'Australia'

SELECT	CountryName, LatestRecordedPopulation, ValidFrom, ValidTo
FROM	Application.Countries_archive
WHERE	CountryName = 'Australia'
UNION ALL
SELECT	CountryName, LatestRecordedPopulation, ValidFrom, ValidTo
FROM	Application.Countries
WHERE	CountryName = 'Australia'

USE TestDB
GO
IF EXISTS (	SELECT * 
FROM 	sys.tables 
WHERE 	name = 'Countries' 
AND temporal_type_desc = 'SYSTEM_VERSIONED_TEMPORAL_TABLE')
BEGIN
	ALTER TABLE Countries SET ( SYSTEM_VERSIONING = OFF)
END
GO

DROP TABLE IF EXISTS Countries_archive
DROP TABLE IF EXISTS Countries
GO

CREATE TABLE Countries (
	CountryID		int IDENTITY PRIMARY KEY
	,CountryName	varchar(50)
	,Population		int
	,ValidFrom		datetime2 GENERATED ALWAYS AS ROW START HIDDEN
	,ValidTo		datetime2 GENERATED ALWAYS AS ROW END HIDDEN
	,PERIOD FOR SYSTEM_TIME (ValidFrom,ValidTo)) 
		WITH(SYSTEM_VERSIONING = ON (HISTORY_TABLE = dbo.Countries_archive))
GO

INSERT Countries (CountryName, Population) VALUES ('Neverland', 100)
UPDATE Countries SET Population = 101 WHERE CountryName = 'Neverland'

SELECT	*, ValidFrom, ValidTo
FROM	Countries
	FOR SYSTEM_TIME ALL
ORDER BY ValidFrom

BEGIN TRAN
	UPDATE Countries SET Population = 102 WHERE CountryName = 'Neverland'
	WAITFOR DELAY '00:00:10'
	UPDATE Countries SET Population = 103 WHERE CountryName = 'Neverland'
COMMIT TRAN

SELECT	*, ValidFrom, ValidTo
FROM	Countries
	FOR SYSTEM_TIME ALL
ORDER BY ValidFrom

SELECT	*
FROM	countries_archive

DECLARE @local_time datetime2
	,@utc_time datetime2
SET @local_time = '2018-07-04 13:40:00'

SET @utc_time = DATEADD(second, DATEDIFF(second, SYSDATETIME(), SYSUTCDATETIME()), @local_time)

SELECT	*	
FROM	Countries
	FOR SYSTEM_TIME AS OF @utc_time

DELETE FROM Countries_archive WHERE ValidTo <DATEADD(yy, -7, SYSUTCDATETIME())

ALTER TABLE Countries ADD Description varchar(100) NULL 
GO
UPDATE Countries SET Description = 'Not an actual country' WHERE CountryName = 'Neverland'

GO
ALTER TABLE Countries DROP COLUMN Description

USE TestDB
GO
IF EXISTS (	SELECT * 
FROM 	sys.tables 
WHERE 	name = 'Countries' 
AND temporal_type_desc = 'SYSTEM_VERSIONED_TEMPORAL_TABLE')
BEGIN
	ALTER TABLE Countries SET ( SYSTEM_VERSIONING = OFF)
END
GO

DROP TABLE IF EXISTS Countries_archive
DROP TABLE IF EXISTS Countries
GO

CREATE TABLE Countries (
	CountryID	int IDENTITY PRIMARY KEY NOT NULL
	,CountryName	varchar(50)
	,Population	int)
GO

INSERT Countries (CountryName, Population) VALUES ('Neverland', 103)

CREATE TABLE Countries_archive (
	CountryID	int NOT NULL --no identity or primary key
	,CountryName	varchar(50)
	,Population	int)
GO

ALTER TABLE Countries_archive ADD ValidFrom datetime2 NOT NULL
ALTER TABLE Countries_archive ADD ValidTo datetime2 NOT NULL
GO
INSERT Countries_archive (CountryID, CountryName, Population, ValidFrom,ValidTo) 
VALUES (1, 'Neverland', 100, '2011-01-01', '2012-01-01') 

ALTER TABLE Countries ADD ValidFrom datetime2  NULL
ALTER TABLE Countries ADD ValidTo datetime2  NULL
GO
UPDATE Countries SET ValidFrom = '2012-01-01' 
UPDATE Countries SET ValidTo = '9999-12-31 23:59:59.9999999'
GO

ALTER TABLE Countries ALTER COLUMN ValidFrom datetime2 NOT NULL
ALTER TABLE Countries ALTER COLUMN ValidTo datetime2 NOT NULL
GO

ALTER TABLE Countries ADD PERIOD FOR SYSTEM_TIME (ValidFrom,ValidTo)
ALTER TABLE Countries SET (SYSTEM_VERSIONING = ON (HISTORY_TABLE = dbo.Countries_archive))

SELECT  [2012].population - [2011].population AS 'population growth'
FROM	Countries FOR SYSTEM_TIME AS OF '2011-01-01' AS [2011]
	INNER JOIN Countries FOR SYSTEM_TIME AS OF '2012-01-01' AS [2012] 
	ON [2011].CountryID = [2012].CountryID

--Query and output JSON data
CREATE TABLE [dbo].[Employees](
	[EmployeeID] [tinyint] IDENTITY(1,1) NOT NULL,
	[FirstName] [varchar](100) NULL,
	[LastName] [varchar](50) NULL,
	[Address] [varchar](100) NULL,
	[Employee_Number] [int] NULL
) 

INSERT dbo.Employees (FirstName, LastName, Address) 
VALUES ('Bob', 'Jackson', 'Under the bridge')
	,('Bo', 'Didley', 'Home of mr. Bo Didley')

DECLARE @json NVARCHAR(MAX)
SET @json = '{"FirstName":"Bob"}'

SELECT ISJSON(@json) AS 'IsValidJSON?'

SELECT	FirstName, lastname, address
FROM	employees
WHERE	EmployeeID = 1
FOR JSON AUTO

--Format query output as JSON
SELECT	FirstName, lastname, address
FROM	employees
WHERE	EmployeeID in (1,2)
FOR JSON AUTO

SELECT	FirstName, lastname, address
FROM	employees
WHERE	EmployeeID in (1,2)
FOR JSON PATH

SELECT	FirstName, lastname, address
FROM	employees
WHERE	EmployeeID in (1,2)
FOR JSON PATH, ROOT ('Employees')

SELECT	FirstName, lastname, address
FROM	employees
WHERE	EmployeeID in (1,2)
FOR JSON PATH, WITHOUT_ARRAY_WRAPPER

UPDATE	Employees 
SET	Employee_Number = employeeID 
WHERE	EmployeeID = 1

SELECT	FirstName, lastname, address, Employee_Number
FROM	employees
WHERE	EmployeeID in (1,2)
FOR JSON PATH,  INCLUDE_NULL_VALUES

SELECT	FirstName AS 'Name.FirstName'
	, lastname AS 'Name.LastName'
	, address
FROM	employees
WHERE	EmployeeID in (1,2)
FOR JSON PATH

--Extract data from JSON
DECLARE @json NVARCHAR(MAX)

SET @json = '{
	"A null value":null
	,"A text string":"string"
	,"A number":2
	,"A boolean (true or false)":true
	,"A boolean (true or false)":false
	,"An array":[1,2,3]
	,"An object": {"key1":"value1", "key2":"value2"}
}'

SELECT	*
FROM	OPENJSON(@json)

SELECT	[key], value
FROM	OPENJSON(@json)
WHERE	type <> 0

SELECT	[key], value
FROM	OPENJSON(@json,'$."An object"')

SELECT	[key], value
FROM	OPENJSON(@json,'$."An array"')

SELECT	[key], value
FROM	OPENJSON(@json,'lax $."n array"')

SELECT	[key], value
FROM	OPENJSON(@json,'strict $."n array"')

SELECT	*
FROM	OPENJSON(@json)
	WITH (
		NameOfTheColumn		bigint		'$."A number"'
		,NameOfTheOtherColumn	varchar(100)	'$."A text string"'
		)

SELECT	*
FROM	OPENJSON(@json)
	WITH (
		NameOfTheColumn		bigint		'$."A number"'
		,NameOfTheOtherColumn	varchar(100)	'$."A text string"'
		,JSONColumn  			nvarchar(max) '$."An object"' AS JSON
		,ObjectValue 			varchar(100) 	'$."An object".key1'
		)

SELECT JSON_VALUE(@json, '$."A number"')

SELECT JSON_QUERY(@json, '$."An object"')

SELECT JSON_QUERY(@json, '$."A number"')
SELECT JSON_VALUE(@json, '$."An object"')

SELECT JSON_MODIFY(@json,'$."A number"', 17)

SELECT JSON_VALUE(@json, '$.Employees[1].address')

--Query and output XML data
DECLARE @xml XML
SET @XML = '<FirstName>Bob</Firstname>'

SELECT @xml

SELECT TRY_CAST('<FirstName>Bob</Firstname>' as XML)

SELECT	EmployeeID as '@Id'
	,FirstName
	,LastName
FROM	Employees
WHERE	EmployeeID in (1,2)
FOR XML PATH ('Employee')

--Format query output as XML
SELECT	EmployeeID 
	,FirstName 
	,LastName
FROM	Employees
WHERE	EmployeeID in (1,2)
FOR XML RAW

SELECT	EmployeeID 
	,FirstName 
	,LastName
FROM	Employees
WHERE	EmployeeID in (1,2)
FOR XML RAW ('GiveThisElementAnotherName')

SELECT	EmployeeID 
	,FirstName 
	,LastName
FROM	Employees
WHERE	EmployeeID in (1,2)
FOR XML RAW , ELEMENTS

SELECT	EmployeeID 
	,FirstName 
	,LastName
	,Employee_Number
FROM	Employees
WHERE	EmployeeID in (1,2)
FOR XML RAW

SELECT	EmployeeID 
	,FirstName 
	,LastName
	,Employee_Number
FROM	Employees
WHERE	EmployeeID in (1,2)
FOR XML RAW, ELEMENTS XSINIL

SELECT	EmployeeID 
	,FirstName 
	,LastName
FROM	Employees
WHERE	EmployeeID in (1,2)
FOR XML RAW, ROOT ('Employees')

SELECT	c.Customername, o.orderid,  OrderDate
FROM	sales.Orders o
	INNER JOIN sales.Customers c on c.CustomerID = o.CustomerID
WHERE	c.customerId in (832, 803)
	AND YEAR(OrderDate)=2013 
	AND MONTH(OrderDate)=1 
--ORDER BY OrderDate
FOR XML AUTO

SELECT	EmployeeID as '@Id'
	,FirstName
	,LastName
FROM	Employees
WHERE	EmployeeID in (1,2)
FOR XML PATH ('Employee')

--outer query
SELECT	c.CustomerID AS '@id'
	,c.Customername
	--subquery will be inserted here
FROM	sales.customers c	
WHERE	c.customerId in (832, 803)
ORDER BY c.CustomerName
FOR XML PATH ('Customers'), ELEMENTS, ROOT ('CustomerOrders')

--subquery
SELECT	o.orderid AS '@OrderID'
	,o.OrderDate 
FROM	sales.customers c2
	INNER JOIN sales.orders o on c2.CustomerID = o.CustomerID
WHERE	c.customerID = c2.customerID
	AND YEAR(OrderDate)=2013 
	AND MONTH(OrderDate)=1 		
FOR XML PATH('Orders'), ROOT('CustomerOrderId'),TYPE

--full query
SELECT	c.CustomerID AS '@id'
		,c.Customername
		,(SELECT	o.orderid AS '@OrderID'
				,o.OrderDate 
			FROM	sales.customers c2
				INNER JOIN sales.orders o on c2.CustomerID = o.CustomerID
			WHERE	c.customerID = c2.customerID
				AND YEAR(OrderDate)=2013 
				AND MONTH(OrderDate)=1 		
			FOR XML PATH('Orders'), ROOT('CustomerOrderId'),TYPE)
FROM	sales.customers c	
WHERE	c.customerId in (832, 803)
ORDER BY c.CustomerName
FOR XML PATH ('Customers'), ELEMENTS, ROOT ('CustomerOrders')

SELECT	ol.orderlineId as '@OrderLineID'
	,ol.Description
	,ol.Quantity
FROM	sales.orderlines ol
	inner join sales.orders o2 on ol.OrderID = o2.OrderID
	inner join sales.customers c3 on c3.CustomerID = o.CustomerID
WHERE	 o2.OrderID = o.orderid
FOR XML PATH ('OrderLines'), TYPE


DECLARE @xml varchar(1000)
DECLARE @xml_document_handle int

SET @xml = '
<CustomerOrders>
  <Customers id="832">
    <Customername>Aakriti Byrraju</Customername>
  </Customers>
  <Customers id="803">
    <Customername>Bala Dixit</Customername>
  </Customers>
</CustomerOrders>
'

-- Step 1
EXEC  sp_xml_preparedocument @xml_document_handle OUTPUT, @xml;  

--Step 2
SELECT    *  
FROM      OPENXML (@xml_document_handle, '/CustomerOrders/Customers',11)  
          WITH (	id		int,  
			Customername	varchar(200)); 

--Step 3
EXEC	sp_xml_removedocument @xml_document_handle

--XML output of customers, orders and order lines
SELECT	c.CustomerID AS '@id'
	,c.Customername
	, (SELECT	o.orderid AS '@OrderID'
			,o.OrderDate 
			,(SELECT ol.orderlineId as '@OrderLineID'
				,ol.Description
				,ol.Quantity
			FROM	sales.orderlines ol
				inner join sales.orders o2 on ol.OrderID = o2.OrderID
				inner join sales.customers c3 
on c3.CustomerID = o.CustomerID
			WHERE	 o2.OrderID = o.orderid
			for XML PATH ('OrderLines'), TYPE
			)
	FROM	sales.customers c2
		INNER JOIN sales.orders o on c2.CustomerID = o.CustomerID
	WHERE	c.customerID = c2.customerID
		AND YEAR(OrderDate)=2013 
		AND MONTH(OrderDate)=1 		
	FOR XML PATH('Orders'), ROOT('CustomerOrderId'),TYPE)
FROM	sales.customers c	
WHERE	c.customerId in (832, 803)
ORDER BY c.CustomerName
FOR XML PATH ('Customers'), ELEMENTS, ROOT ('CustomerOrders')

DECLARE @xml varchar(max)
DECLARE @xml_document_handle int

SET @xml = '
<CustomerOrders>
  <Customers id="832">
    <Customername>Aakriti Byrraju</Customername>
    <CustomerOrderId>
      <Orders OrderID="1">
        <OrderDate>2013-01-02</OrderDate>
        <OrderLines OrderLineID="2">
          <Description>Ride on toy sedan car (Black) 1/12 scale</Description>
          <Quantity>10</Quantity>
        </OrderLines>
      </Orders>
      <Orders OrderID="45">
        <OrderDate>2013-01-01</OrderDate>
        <OrderLines OrderLineID="1">
          <Description>32 mm Double sided bubble wrap 50m</Description>
          <Quantity>50</Quantity>
        </OrderLines>
      </Orders>
    </CustomerOrderId>
  </Customers>
  <Customers id="803">
    <Customername>Bala Dixit</Customername>
    <CustomerOrderId>
      <Orders OrderID="2">
        <OrderDate>2013-01-01</OrderDate>
        <OrderLines OrderLineID="3">
          <Description>Developer joke mug - old C developers never die (White)</Description>
          <Quantity>9</Quantity>
        </OrderLines>
        <OrderLines OrderLineID="6">
          <Description>USB food flash drive - chocolate bar</Description>
          <Quantity>9</Quantity>
        </OrderLines>
      </Orders>
    </CustomerOrderId>
  </Customers>
</CustomerOrders>
'

-- Step 1
EXEC  sp_xml_preparedocument @xml_document_handle OUTPUT, @xml;  

--Step 2
SELECT    *  
FROM      OPENXML (@xml_document_handle, '/CustomerOrders/Customers/CustomerOrderId/Orders/OrderLines',11)  
          WITH (	id	int '../../../@id',  
			Customername	varchar(1000) '../../../Customername',
			OrderDate	date '../OrderDate',
			OrderID	int '../@OrderID', 
			Description	varchar(1000)); 

--Step 3
EXEC	sp_xml_removedocument @xml_document_handle


--XQuery
SELECT @xml.query('/CustomerOrders/Customers/CustomerOrderId/Orders/OrderLines')

SELECT @xml.query('(/CustomerOrders/Customers/CustomerOrderId/Orders/OrderLines)[2]')

SELECT @xml.query('(/CustomerOrders/Customers[2]/CustomerOrderId/Orders/OrderLines)[2]')

SELECT @xml.query('(/CustomerOrders/Customers[@id=803]/CustomerOrderId/Orders/OrderLines)')

SELECT @xml.query('(/CustomerOrders/Customers[Customername="Bala Dixit"]/CustomerOrderId/Orders/OrderLines)')

--FLWOR
SELECT @xml.query('
		for $Orders in /CustomerOrders/Customers/CustomerOrderId/Orders
		return ($Orders)
		')

SELECT @xml.query('
for $Orders in /CustomerOrders/Customers/CustomerOrderId/Orders
return string($Orders)
')

SELECT @xml.query('
	for $Orders in /CustomerOrders/Customers/CustomerOrderId/Orders
	let $Quantity :=$Orders/OrderLines/Quantity
	where $Quantity > 20
	return ($Orders)
	')

SELECT @xml.query('
		for $Orders in /CustomerOrders/Customers/CustomerOrderId/Orders
		order by $Orders/@OrderID
		return $Orders
		')

--XQuery value
SELECT @xml.value('(/CustomerOrders/Customers[2]/CustomerOrderId/Orders/OrderLines)[1]', 'varchar(1000)')

SELECT @xml.value('(/CustomerOrders/Customers[2]/CustomerOrderId/Orders/OrderLines)[1]', 'int')

--XQuery exist
SELECT @xml.exist('(/CustomerOrders/Customers/CustomerOrderId/Orders/OrderLines)[5]')

SELECT @xml.exist('(/CustomerOrders/Customers[@id] = 832)')

--XQuery nodes
SELECT XML_table.value('../../../@id', N'int') as customerid
	,XML_table.value('../../../Customername[1]', 'varchar(100)') as customername
	,XML_table.value('../@OrderID', 'varchar(100)') as Orderid
	,XML_table.value('@OrderLineID', 'varchar(100)') as OrderLineid
	,XML_table.value('Quantity[1]', 'varchar(100)') as quantity
	,XML_table.value('Description[1]', 'varchar(100)') as description
FROM    @xml.nodes('/CustomerOrders/Customers/CustomerOrderId/Orders/OrderLines') as t(XML_table)
ORDER BY customerid desc

SELECT XML_table.value('../../@id', N'int') as customerid
	,XML_table.value('@OrderID', N'int') as orderID
	,XML_table.query('.') as orderdetails
FROM   @xml.nodes('/CustomerOrders/Customers/CustomerOrderId/Orders') as t(XML_table)

--XQuery modify
DECLARE @xml XML

SET @xml = '
<Employees>
	<Employee Id="1">
	  <FirstName>Bob</FirstName>
	  <LastName>Jackson</LastName>
	</Employee>
	<Employee Id="2">
	  <FirstName>Bo</FirstName>
	  <LastName>Didley</LastName>
	</Employee>
</Employees>
'
SET @xml.modify('
insert attribute SSID {"idontknow"}
into (/Employees/Employee)[2]
')

SET @xml.modify('
insert <Employee Id="3"><FirstName>Jeff</FirstName><LastName>Williams</LastName></Employee>
after (/Employees/Employee)[2]
')

SET @xml.modify('
insert <Employee Id="3"><FirstName>Jeff</FirstName><LastName>Williams</LastName></Employee>
into (/Employees)[1]
')


--XQuery delete
SET @xml.modify('
delete /Employees/Employee[2]/@SSID
')

SET @xml.modify('
delete /Employees/Employee[2]/Address
')
If the element or attribute isn’t present, no error will be returned.

SET @xml.modify('
replace value of (/Employees/Employee[2]/@SSID)[1]
with "001-002-003"
')

SET @xml.modify('
replace value of (/Employees/Employee[2]/Address/text())[1]
with "Beverly Hills"
')

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USE WideWorldImporters;

/* Query data by using subqueries and APPLY */

-- 001

-- simple subquery

SELECT o.*

FROM (SELECT * FROM Sales.Orders) o

-- 002

SELECT *

FROM [Application].[People]

WHERE PreferredName IN ( SELECT CustomerName

FROM sales.Customers )

-- 003

USE TestDB;

SELECT *

,(SELECT AVG(salary) FROM dbo.Employees) AS average_salary

FROM dbo.Employees

-- 004

SELECT *

FROM dbo.Employees

WHERE Salary > (SELECT AVG(salary) FROM dbo.Employees)

-- 005

-- correlated subquery

SELECT *

FROM dbo.Employees e1

WHERE Salary > ( SELECT AVG(salary)

FROM Employees e2

WHERE e1.department = e2.department)

-- 006

SELECT *

FROM dbo.Employees e1

INNER JOIN (SELECT AVG(salary) AS avg_salary, department

FROM dbo.employees

GROUP BY department) e2 ON e1.Department = e2.Department

WHERE salary > e2.avg_salary

-- 007

SELECT *

, (SELECT AVG(salary) FROM Employees e2 WHERE e1.department = e2.Department)

FROM Employees e1

WHERE Salary > ( SELECT AVG(salary)

FROM Employees e2

WHERE e1.Department = e2.department)

-- 008

SELECT *

FROM Departments d

WHERE ( SELECT count (*)

FROM Employees e

WHERE e.Department = d.Department) > 2

-- 009

ALTER TABLE Departments ADD Location varchar(100) DEFAULT 'Houston' WITH VALUES;

UPDATE Departments

SET Location = 'New York'

WHERE Department = 'Management'

/* Evaluate performance differences between table joins and correlated subqueries based on provided data and query plans */

-- 010

SELECT *

INTO Customers_copy

FROM WideWorldImporters.sales.Customers

SELECT *

INTO orders_copy

FROM WideWorldImporters.sales.orders

-- 011

-- join faster

SELECT c.CustomerName, o.lastorderdate, o.NumberOfOrders

FROM (SELECT customerID, max(orderdate) AS LastOrderDate, count(*) AS NumberOfOrders

FROM orders_copy

GROUP BY CustomerID) o

INNER JOIN Customers_copy c on c.CustomerID = o.customerId

SELECT CustomerName

,( SELECT MAX(orderdate)

FROM orders_copy o

WHERE c.customerId = o.customerID ) AS LastOrderDate

,( SELECT COUNT(*)

FROM orders_copy o

WHERE c.customerId = o.customerID )AS NumberOfOrders

FROM Customers_copy c

-- 012

-- correlated subquery faster

SELECT *

FROM Customers_copy c

LEFT OUTER JOIN orders_copy o on c.CustomerID = o.CustomerID

WHERE o.CustomerID IS NULL

SELECT *

FROM Customers_copy c

WHERE NOT EXISTS ( SELECT *

FROM orders_copy o

WHERE c.CustomerID = o.CustomerID)

/* Distinguish between the use of CROSS APPLY and OUTER APPLY */

-- 013

SELECT *

FROM Departments d

CROSS APPLY

( SELECT *

FROM Employees e

WHERE e.Department = d.Department) table_alias

SELECT *

FROM Departments d

INNER JOIN Employees e ON d.Department = e.Department

-- 014

INSERT Departments VALUES ('Research', 'Eindhoven')

SELECT *

FROM Departments d

OUTER APPLY

( SELECT *

FROM Employees e

WHERE e.Department = d.Department) table_alias

SELECT *

FROM Departments d

LEFT OUTER JOIN Employees e ON d.Department = e.Department

-- 015

CREATE FUNCTION dbo.fn_GetListOfEmployees(@Department AS varchar(100))

RETURNS TABLE

RETURN

(

SELECT FirstName + ' ' + LastName AS FullName, Salary

FROM Employees e

WHERE e.Department = @Department

)

-- 016

SELECT *

FROM dbo.fn_GetListOfEmployees('Engineering')

-- 017

SELECT *

FROM Departments d

CROSS APPLY dbo.fn_GetListOfEmployees(d.Department)

-- 018

SELECT session_id, DB_NAME(database_id) AS [database], start_time

, open_transaction_count, [text] AS [Query]

FROM sys.dm_exec_requests r

CROSS APPLY sys.dm_exec_sql_text(r.plan_handle) s

WHERE session_id > 50 -- Exclude system spids

ORDER BY session_id;

/* Query data by using table expressions */

--Identify basic components of table expressions

SELECT o.*

FROM (SELECT * FROM Sales.Orders) o

-- common table expression

WITH o

AS ( SELECT *

FROM Sales.Orders)

SELECT *

FROM o

SELECT *

FROM dbo.Employees e1

WHERE Salary > ( SELECT AVG(salary)

FROM Employees e2

WHERE e1.Department = e2.department);

-- readability example

SELECT c.CustomerName, o.lastorderdate, o.NumberOfOrders

FROM (SELECT customerID, max(orderdate) AS LastOrderDate, count(*) AS NumberOfOrders

FROM orders_copy

GROUP BY CustomerID) o

INNER JOIN Customers_copy c on c.CustomerID = o.customerId;

WITH o AS (

SELECT customerID, max(orderdate) AS LastOrderDate, count(*) AS NumberOfOrders

FROM orders_copy

GROUP BY CustomerID)

SELECT c.CustomerName, o.lastorderdate, o.NumberOfOrders

FROM o

INNER JOIN Customers_copy c on c.CustomerID = o.customerId

--Construct recursive table expressions to meet business requirements

-- Recursive cte, top to bottom:

ALTER TABLE Employees ADD ManagerID tinyint NULL;

INSERT Employees (FirstName,LastName, Salary, Department, ManagerID)

VALUES ('Harriet', 'Hughes', 1800.00,'Sales',7);

INSERT Employees (FirstName,LastName, Salary, Department, ManagerID)

VALUES ('Ronnie', 'Robertson', 1800.00,'Engineering',7);

UPDATE Employees

SET ManagerID = (SELECT EmployeeID FROM Employees WHERE FirstName = 'Harriet')

WHERE Department = 'Sales' AND FirstName <> 'Harriet'

UPDATE Employees

SET ManagerID = (SELECT EmployeeID FROM Employees WHERE FirstName = 'Ronnie')

WHERE Department = 'Engineering' AND FirstName <> 'Ronnie'

ALTER TABLE Employees ADD CONSTRAINT PK_EmployeeID PRIMARY KEY (EmployeeID)

ALTER TABLE Employees ADD CONSTRAINT FK_EmployeeID FOREIGN KEY (ManagerID) REFERENCES Employees(EmployeeID)

WITH Employee_CTE AS (

SELECT EmployeeID, ManagerID, Firstname + ' ' + LastName AS Name, 0 as Level

FROM Employees

WHERE ManagerID IS NULL

UNION ALL

SELECT e1.EmployeeID, e1.ManagerID, Firstname + ' ' + LastName, e2.level + 1

FROM Employees e1

INNER JOIN Employee_CTE e2 ON e2.EmployeeID = e1.ManagerID

)

SELECT Name, Level

FROM Employee_CTE

ORDER BY Level, Name

-- Recursive cte, bottom to top:

WITH Employee_CTE AS (

SELECT EmployeeID, ManagerID, Firstname + ' ' + LastName AS Name, 0 as Level

FROM Employees

WHERE EmployeeID NOT IN (SELECT ManagerID FROM Employees WHERE ManagerID IS NOT NULL)

UNION ALL

SELECT e1.EmployeeID, e1.ManagerID, Firstname + ' ' + LastName, e2.level + 1

FROM Employees e1

INNER JOIN Employee_CTE e2 ON e1.EmployeeID = e2.ManagerID

)

SELECT DISTINCT Name, Level

FROM Employee_CTE

ORDER BY Level, Name

-- Recursive CTE, final example

WITH Employee_CTE AS (

SELECT EmployeeID, ManagerID, 0 as Level

FROM Employees

WHERE EmployeeID NOT IN (SELECT ManagerID FROM Employees WHERE ManagerID IS NOT NULL)

UNION ALL

SELECT e1.EmployeeID, e1.ManagerID, e2.level + 1

FROM Employees e1

INNER JOIN Employee_CTE e2 ON e1.EmployeeID = e2.ManagerID

)

Distinct_CTE AS (

SELECT DISTINCT EmployeeID, ManagerID, Level

FROM Employee_CTE)

SELECT e2.FirstName + ' ' + e2.LastName AS Name, e3.FirstName + ' ' + e3.LastName AS Manager, Level

FROM Distinct_CTE e1

INNER JOIN Employees e2 ON e1.employeeID = e2.EmployeeID

LEFT OUTER JOIN Employees e3 ON e1.ManagerID = e3.EmployeeID

ORDER BY Level, Name

--multiple CTEs

WITH Employee_CTE AS (

SELECT EmployeeID, ManagerID, 0 as Level

FROM Employees

WHERE EmployeeID NOT IN ( SELECT ManagerID

FROM Employees

WHERE ManagerID IS NOT NULL)

UNION ALL

SELECT e1.EmployeeID, e1.ManagerID, e2.level + 1

FROM Employees e1

INNER JOIN Employee_CTE e2 ON e1.EmployeeID = e2.ManagerID

)

Distinct_CTE AS (

SELECT DISTINCT EmployeeID, ManagerID, Level

FROM Employee_CTE)

SELECT e2.FirstName + ' ' + e2.LastName AS Name

, e3.FirstName + ' ' + e3.LastName AS Manager, Level

FROM Distinct_CTE e1

INNER JOIN Employees e2 ON e1.employeeID = e2.EmployeeID

LEFT OUTER JOIN Employees e3 ON e1.ManagerID = e3.EmployeeID

ORDER BY Level, Name

--Temporary table

SELECT *

INTO #tmp_Employees

FROM Employees

SELECT *

FROM #tmp_Employees

ALTER TABLE #tmp_Employees ADD Description varchar(100) NULL

DROP TABLE #tmp_Employees

SELECT *

FROM tempdb.sys.objects

WHERE name LIKE '#tmp_Employees%'

--Table variables

DECLARE @Employees TABLE (

[EmployeeID] [tinyint] NOT NULL,

[FirstName] [varchar](100) NULL,

[LastName] [varchar](50) NULL,

[Address] [varchar](100) NULL,

[Salary] [decimal](18, 2) NULL,

[Department] [varchar](100) NULL,

[Employee_Number] [int] NULL,

[ManagerID] [tinyint] NULL)

INSERT INTO @Employees

SELECT *

FROM Employees

--Group and pivot data by using queries

--Construct complex GROUP BY clauses using GROUPING SETS, and CUBE

DROP TABLE IF EXISTS UFO_Sightings;

CREATE TABLE UFO_Sightings (

CountryID tinyint

, Country varchar(50)

, State varchar(50)

, City varchar(50)

, UFO_Sightings int );

INSERT INTO UFO_Sightings VALUES (1, 'Germany', NULL, 'Berlin', 1)

INSERT INTO UFO_Sightings VALUES (1, 'Germany', NULL, 'Frankfurt', 2)

INSERT INTO UFO_Sightings VALUES (1, 'Germany', NULL, 'Frankfurt', 3)

INSERT INTO UFO_Sightings VALUES (2, 'United States', 'Texas', 'Houston', 1)

INSERT INTO UFO_Sightings VALUES (2, 'United States', 'Texas', 'Paris', 2)

INSERT INTO UFO_Sightings VALUES (2, 'United States', 'Nevada', NULL, 300)

INSERT INTO UFO_Sightings VALUES (3, 'France', NULL, 'Paris', 1);

SELECT *

FROM UFO_Sightings

SELECT Country, SUM(UFO_Sightings)

FROM UFO_Sightings

GROUP BY Country

SELECT SUM(UFO_Sightings)

FROM UFO_Sightings

SELECT SUM(UFO_Sightings)

FROM UFO_Sightings

GROUP BY ()

SELECT Country, City, SUM(UFO_Sightings)

FROM UFO_Sightings

GROUP BY Country, City

ORDER BY Country, City;

SELECT Country, SUM(UFO_Sightings)

FROM UFO_Sightings

WHERE City <> 'Paris'

GROUP BY Country

SELECT Country, SUM(UFO_Sightings)

FROM UFO_Sightings

WHERE ISNULL(City,'') <> 'Paris'

GROUP BY Country

SELECT CountryID, Country, SUM(UFO_Sightings)

FROM UFO_Sightings

GROUP BY Country

SELECT Country, SUM(UFO_Sightings) AS TotalNumberOfSightings

FROM UFO_Sightings

GROUP BY Country

HAVING SUM(UFO_Sightings) > 100;

WITH ufo AS (

SELECT Country, SUM(UFO_Sightings) AS TotalNumberOfSightings

FROM UFO_Sightings

GROUP BY Country)

SELECT *

FROM ufo

WHERE TotalNumberOfSightings > 100

INSERT INTO UFO_Sightings VALUES (4, 'Belgium', NULL, 'Brussels', NULL);

SELECT Country, COUNT(UFO_Sightings) AS Count_1, COUNT(*) AS Count_2

FROM UFO_Sightings

GROUP BY Country

SELECT Country, State, SUM(UFO_Sightings) AS TotalUFO_Sightings

FROM UFO_Sightings

GROUP BY Country, State

--complex GROUP BY logic

SELECT Country, City, SUM(UFO_Sightings) AS TotalUFO_Sightings

FROM UFO_Sightings

GROUP BY Country, City

ORDER BY Country, City

SELECT Country, City, SUM(UFO_Sightings) AS TotalUFO_Sightings

FROM UFO_Sightings

GROUP BY ROLLUP (Country, City);

SELECT Country, NULL AS City, SUM(UFO_Sightings) AS TotalUFO_Sightings

FROM UFO_Sightings

GROUP BY Country

UNION ALL

SELECT Country, City, SUM(UFO_Sightings) AS TotalUFO_Sightings

FROM UFO_Sightings

GROUP BY Country, City

UNION ALL

SELECT NULL, NULL, SUM(UFO_Sightings) AS TotalUFO_Sightings

FROM UFO_Sightings

GROUP BY ()

GROUP BY Country, City WITH ROLLUP;

SELECT Country, GROUPING(Country) AS Is_result_of_grouping_countries

, State, GROUPING(State) AS Is_result_of_grouping_cities

FROM UFO_Sightings

GROUP BY Country, State WITH ROLLUP

SELECT CASE

WHEN GROUPING(Country) = 1 THEN 'Grand Total'

WHEN GROUPING(State) = 1 THEN 'Total for ' + Country

ELSE ''

END AS Totals

, Country

, State

,SUM(UFO_Sightings) AS TotalUFO_Sightings

FROM UFO_Sightings

GROUP BY Country, State WITH ROLLUP

SELECT Country, State, GROUPING_ID(Country, State )

FROM UFO_Sightings

GROUP BY Country, State WITH ROLLUP

ALTER TABLE UFO_Sightings ADD Continent varchar(100) NULL

GO --required batch separator, otherwise query will fail on missing column

UPDATE UFO_Sightings

SET Continent = 'Europe'

WHERE Country IN ('Germany', 'France', 'Belgium')

UPDATE UFO_Sightings

SET Continent = 'North America'

WHERE Country IN ('United States')

SELECT Continent

, Country

, State

, GROUPING_ID(Continent, Country, State )

, GROUPING(Continent) * 4 + GROUPING(Country) * 2 + GROUPING(State)

FROM UFO_Sightings

GROUP BY Continent, Country, State WITH ROLLUP

SELECT Country, City, SUM(UFO_Sightings) AS TotalUFO_Sightings

FROM UFO_Sightings

GROUP BY CUBE (Country, City)

ORDER BY 1, 2;

-- CUBE dissected: A & NULL, NULL & B, A & B, NULL & NULL

SELECT Country, NULL AS City, SUM(UFO_Sightings) AS TotalUFO_Sightings

FROM UFO_Sightings

GROUP BY (Country)

UNION ALL

SELECT NULL, City, SUM(UFO_Sightings) AS TotalUFO_Sightings

FROM UFO_Sightings

GROUP BY ( City)

UNION ALL

SELECT Country, City, SUM(UFO_Sightings) AS TotalUFO_Sightings

FROM UFO_Sightings

GROUP BY Country, City

UNION ALL

SELECT NULL, NULL, SUM(UFO_Sightings) AS TotalUFO_Sightings

FROM UFO_Sightings

ORDER BY 1, 2

SELECT Continent

, Country

, City

, SUM(UFO_Sightings) AS TotalUFO_Sightings

, GROUPING_ID(Continent,Country, City)

FROM UFO_Sightings

GROUP BY CUBE (Continent, Country, City)

ORDER BY 5;

SELECT Country, City, SUM(UFO_Sightings) AS TotalUFO_Sightings

FROM UFO_Sightings

GROUP BY GROUPING SETS ( Country, City)

SELECT Country, NULL, SUM(UFO_Sightings) AS TotalUFO_Sightings

FROM UFO_Sightings

GROUP BY Country

UNION ALL

SELECT NULL, City, SUM(UFO_Sightings) AS TotalUFO_Sightings

FROM UFO_Sightings

GROUP BY City

SELECT Country, City, SUM(UFO_Sightings) AS TotalUFO_Sightings

FROM UFO_Sightings

GROUP BY GROUPING SETS ( Country, City, ())

--Use windowing functions to group and rank the results of a query

DROP TABLE IF EXISTS Runner_info

CREATE TABLE Runner_info (

Runner varchar(50)

,Nickname varchar(50)

,Race varchar(50)

,Race_date date

,Distance decimal(8,3)

,Finish_time time)

INSERT Runner_info VALUES ('Jack', 'The Flash', 'New York marathon', '2016-11-06', 42.195, '2:53:00')

INSERT Runner_info VALUES ('Jack', 'The Flash', 'New York marathon', '2017-11-05', 42.195, '2:55:00')

INSERT Runner_info VALUES ('Jack', 'The Flash', 'Berlin marathon', '2016-09-25', 42.195, '2:45:00')

INSERT Runner_info VALUES ('Juan Gonzalez', 'Speedy', 'New York marathon', '2016-11-06', 42.195, '3:22:00')

INSERT Runner_info VALUES ('Juan Gonzalez', 'Speedy', 'New York marathon', '2017-11-05', 42.195, '3:18:30')

INSERT Runner_info VALUES ('Rudy', 'Roadrunner', 'New York marathon', '2016-11-06', 42.195, '4:01:00')

INSERT Runner_info VALUES ('Rudy', 'Roadrunner', 'New York marathon', '2017-11-05', 42.195, '4:05:30')

INSERT Runner_info VALUES ('Rudy', 'Roadrunner', 'Berlin marathon', '2016-09-25', 42.195, '3:59:59')

INSERT Runner_info VALUES ('Rudy', 'Roadrunner', 'Berlin marathon', '2017-09-24', 42.195, '4:13:00')

INSERT Runner_info VALUES ('Rudy', 'Roadrunner', 'Rotterdam half marathon', '2017-04-07', 21.1, '1:52')

SELECT *

FROM Runner_info

SELECT *

,COUNT(*) OVER () AS Nr_of_races_total

FROM Runner_info

SELECT *

,COUNT(*) OVER () AS Nr_of_races_total

,COUNT(*) OVER (PARTITION BY Runner) AS Nr_of_races_per_runner

FROM Runner_info

SELECT *

,COUNT(*) OVER (PARTITION BY Runner) AS Nr_of_races_per_runner

FROM Runner_info

WHERE Distance = 42.195

SELECT Runner

,Race

,Race_date

,Finish_time

,MIN(Finish_time) OVER (PARTITION BY Runner, Race) AS Race_PR

,DATEDIFF(mi,MIN(Finish_time) OVER (PARTITION BY Runner, Race), Finish_time) AS Slower_than_PR

FROM Runner_info

OVER ( PARTITION BY column

ORDER BY column

ROWS BETWEEN … AND …)

SELECT Runner, Race, Race_date, distance

,SUM(distance) OVER (PARTITION BY Runner

ORDER BY Race_date

ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW)

AS Cumulative_distance

FROM Runner_info

WHERE Runner = 'Rudy'

ORDER BY Runner, Race_date

SELECT Runner, Race, Race_date, distance

,AVG(distance) OVER (PARTITION BY Runner

ORDER BY Race_date

ROWS BETWEEN 2 PRECEDING AND 2 FOLLOWING)

AS Running_average

FROM Runner_info

WHERE Runner = 'Rudy'

ORDER BY Runner, Race_date

INSERT Runner_info VALUES ('Rudy', 'Roadrunner', 'Ran home', '2017-11-05', 10, '1:10')

SELECT Runner, Race, Race_date, distance

,SUM(distance) OVER (PARTITION BY Runner

ORDER BY Race_date

ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW)

AS Cumulative_distance

FROM Runner_info

WHERE Runner = 'Rudy'

ORDER BY Runner, Race_date

SELECT Runner, Race, Race_date, distance

,SUM(distance) OVER (PARTITION BY Runner

ORDER BY Race_date

RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW)

AS Cumulative_distance

FROM Runner_info

WHERE Runner = 'Rudy'

ORDER BY Runner, Race_date

--Ranking window functions

SELECT Runner, Race, Race_date, Finish_time

,ROW_NUMBER() OVER (ORDER BY Finish_time) AS rownumber

,RANK() OVER (ORDER BY Finish_time) AS rank

,DENSE_RANK() OVER (ORDER BY Finish_time) AS denserank

,NTILE(5) OVER (ORDER BY Finish_time) AS ntile

FROM Runner_info

WHERE Distance = 42.195

ORDER BY rownumber

INSERT Runner_info VALUES ('Fred', 'The Shadow', 'New York marathon', '2016-11-06', 42.195, '2:53:00')

--Analytic window functions

SELECT FirstName, LastName, Department, Salary

FROM dbo.Employees

SELECT FirstName, LastName, Department, Salary

,LAG(Salary) OVER (ORDER BY Salary) as lag

,LEAD(Salary) OVER (ORDER BY Salary) as lead

FROM Employees

SELECT FirstName, LastName, Department, Salary

,LAG(Salary) OVER (ORDER BY Salary) as lag

,LEAD(Salary) OVER (ORDER BY Salary) as lead

FROM Employees

ORDER BY LastName

SELECT FirstName, LastName, Department, Salary

,LAG(Salary, 2) OVER (ORDER BY Salary) as lag

,LEAD(Salary, 2) OVER (ORDER BY Salary) as lead

FROM Employees

SELECT FirstName, LastName, Department, Salary

,LAG(Salary, 2, 'not applicable') OVER (ORDER BY Salary) as lag

,LEAD(Salary, 2, 'not applicable') OVER (ORDER BY Salary) as lead

FROM Employees

SELECT FirstName, LastName, Department, Salary

,LAG(Salary) OVER (PARTITION BY Department ORDER BY Salary) as lag

,LEAD(Salary) OVER (PARTITION BY Department ORDER BY Salary) as lead

FROM Employees

ORDER BY Department

SELECT FirstName, LastName, Department, Salary

,FIRST_VALUE(FirstName + ' ' + LastName)

OVER ( PARTITION BY Department

ORDER BY Salary)

as Least_earning_employee

,LAST_VALUE(FirstName + ' ' + LastName)

OVER ( PARTITION BY Department

ORDER BY Salary

RANGE BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING)

as Most_earning_employee

FROM Employees

ORDER BY Department, Salary

SELECT FirstName, LastName, Department, Salary

,CUME_DIST() OVER (ORDER BY Salary) as cumulative_distance

,CUME_DIST() OVER (ORDER BY Salary) * COUNT(*) OVER () as equal_or_less

FROM Employees

ORDER BY Salary

INSERT dbo.Employees (FirstName, LastName, Salary, Department)

VALUES ('James', 'Peterson', 900, 'Engineering')

SELECT FirstName, LastName, Department, Salary

,PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BY Salary) OVER () as median_salary

,PERCENTILE_DISC(0.5) WITHIN GROUP (ORDER BY Salary) OVER () as median_salary

FROM Employees

ORDER BY Salary

SELECT FirstName, LastName, Department, Salary

,PERCENT_RANK() OVER (ORDER BY Salary) as fraction_lower_than_this

,CAST(PERCENT_RANK() OVER (ORDER BY Salary) * 100 AS dec(5,1))

as percentage_lower_than_this

FROM Employees

ORDER BY Salary

--Construct PIVOT and UNPIVOT statements to return desired results based on supplied data

SELECT CustomerName, si.StockItemName, sum(quantity) as quantity

FROM sales.Customers c

INNER JOIN sales.Orders o on c.CustomerID = o.CustomerID

INNER JOIN sales.OrderLines ol on o.OrderID = ol.OrderID

INNER JOIN Warehouse.StockItems si on ol.StockItemID = si.StockItemID

WHERE c.CustomerID IN ( SELECT TOP 5 CustomerID

FROM Sales.Orders

GROUP BY CustomerID

ORDER BY COUNT(*))

AND si.StockItemID IN ( SELECT TOP 5 StockItemID

FROM Sales.Orderlines

GROUP BY StockItemID

ORDER BY COUNT(*))

GROUP BY CustomerName, si.StockItemName

ORDER BY CustomerName, si.StockItemName

--PIVOT and UNPIVOT

WITH cte AS(

SELECT CustomerName, si.StockItemName, quantity

FROM sales.Customers c

INNER JOIN sales.Orders o on c.CustomerID = o.CustomerID

INNER JOIN sales.OrderLines ol on o.OrderID = ol.OrderID

INNER JOIN Warehouse.StockItems si on ol.StockItemID = si.StockItemID

WHERE si.StockItemID IN ( SELECT TOP 5 StockItemID

FROM Sales.Orderlines

GROUP BY StockItemID

ORDER BY COUNT(*))

)

SELECT *

FROM cte

PIVOT (SUM(quantity)

FOR CustomerName IN ([Anand Mudaliyar],[Jibek Juniskyzy]

,[Agrita Abele],[Kalyani Benjaree],[Jaroslav Fisar]))

AS SalesQuantity

USE TestDB

DROP TABLE IF EXISTS Sales;

CREATE TABLE Sales(

Customer varchar(50)

, Product varchar(50)

, Quantity int)

INSERT INTO Sales(Customer, Product, Quantity)

VALUES('John','Apples',4)

,('John','Bananas',7)

,('John','Cantaloupe',1)

,('John','Apples',5)

,('John','Beer',6)

,('Bill','Cantaloupe',3)

,('Bill','Beer',24)

,('Diana','Apples',6)

,('Diana','Bananas',5)

,('Diana','Cantaloupe',2)

SELECT *

FROM Sales

-- Pivot customers

SELECT Product, Bill, John, Diana

FROM Sales

PIVOT (SUM(Quantity)

FOR Customer IN (Bill, John, Diana)) AS some_alias

ORDER BY Product

-- Pivot product

SELECT Customer, Apples, Bananas, Cantaloupe , Beer, [Magic mushrooms]

FROM Sales

PIVOT (SUM(Quantity)

FOR Product IN (Apples, Bananas, Cantaloupe , Beer, [Magic mushrooms])) AS some_alias

ORDER BY Customer

-- adding a column

ALTER TABLE Sales ADD CustomerID int NULL

UPDATE Sales SET CustomerID = 1 WHERE Customer = 'Bill'

UPDATE Sales SET CustomerID = 2 WHERE Customer = 'John'

UPDATE Sales SET CustomerID = 3 WHERE Customer = 'Diana'

SELECT Product, Bill, John, Diana

FROM Sales

PIVOT (SUM(Quantity)

FOR Customer IN (Bill, John, Diana)) AS some_alias

ORDER BY Product

ALTER TABLE Sales DROP CustomerID

SELECT Customer, Apples, Bananas, Cantaloupe , Beer, [Magic mushrooms]

INTO Pivoted_sales_table

FROM Sales

PIVOT (SUM(Quantity)

FOR Product IN (Apples, Bananas, Cantaloupe , Beer, [Magic mushrooms])) AS some_alias

ORDER BY Customer

SELECT *

FROM Pivoted_sales_table

SELECT Customer, Product, Quantity

FROM Pivoted_sales_table

UNPIVOT( Quantity FOR

Product IN ( Apples, Bananas, Cantaloupe

, Beer, [Magic mushrooms])

) AS some_alias

--Determine the impact of NULL values in PIVOT and UNPIVOT queries

--Count(*) not allowed

SELECT Product, Bill, John, Diana

FROM Sales

PIVOT (COUNT(Quantity)

FOR Customer IN (Bill, John, Diana)) AS some_alias

ORDER BY Product

SELECT Customer, Apples, Bananas, Cantaloupe , Beer, [Magic mushrooms]

FROM Sales

PIVOT (MIN(Quantity), MAX(Quantity)

FOR Product IN (Apples, Bananas, Cantaloupe , Beer, [Magic mushrooms])) AS some_alias

ORDER BY Customer

USE TestDB

DROP TABLE IF EXISTS Sales;

DROP TABLE IF EXISTS Pivoted_sales_table;

--Query temporal data and non-relational data

--Query historic data by using temporal tables

USE WideWorldImporters

SELECT CountryName, LatestRecordedPopulation

FROM Application.Countries

SELECT CountryName, LatestRecordedPopulation

FROM Application.Countries

FOR SYSTEM_TIME AS OF '2013-01-01 00:00:00.0000000'

WHERE CountryName = 'Australia'

SELECT CountryName, LatestRecordedPopulation, ValidFrom, ValidTo

FROM Application.Countries

FOR SYSTEM_TIME ALL

WHERE CountryName = 'Australia'

SELECT CountryName, LatestRecordedPopulation, ValidFrom, ValidTo

FROM Application.Countries

FOR SYSTEM_TIME FROM '2013-07-01 16:00:00.0000000'

TO '2015-07-01 16:00:00.0000000'

WHERE CountryName = 'Australia'

SELECT CountryName, LatestRecordedPopulation, ValidFrom, ValidTo

FROM Application.Countries

FOR SYSTEM_TIME BETWEEN '2013-07-01 16:00:00.0000000'

AND '2015-07-01 16:00:00.0000000'

WHERE CountryName = 'Australia'

DECLARE @now datetime2 = SYSDATETIME()

SELECT CountryName, LatestRecordedPopulation, ValidFrom, ValidTo

FROM Application.Countries

FOR SYSTEM_TIME CONTAINED IN ('2013-07-01 15:00:00.0000000', @now)

WHERE CountryName = 'Australia'

SELECT CountryName, LatestRecordedPopulation, ValidFrom, ValidTo

FROM Application.Countries_archive

WHERE CountryName = 'Australia'

UNION ALL

SELECT CountryName, LatestRecordedPopulation, ValidFrom, ValidTo

FROM Application.Countries

WHERE CountryName = 'Australia'

USE TestDB

IF EXISTS ( SELECT *

FROM sys.tables

WHERE name = 'Countries'

AND temporal_type_desc = 'SYSTEM_VERSIONED_TEMPORAL_TABLE')

BEGIN

ALTER TABLE Countries SET ( SYSTEM_VERSIONING = OFF)

END

DROP TABLE IF EXISTS Countries_archive

DROP TABLE IF EXISTS Countries

CREATE TABLE Countries (

CountryID int IDENTITY PRIMARY KEY

,CountryName varchar(50)

,Population int

,ValidFrom datetime2 GENERATED ALWAYS AS ROW START HIDDEN

,ValidTo datetime2 GENERATED ALWAYS AS ROW END HIDDEN

,PERIOD FOR SYSTEM_TIME (ValidFrom,ValidTo))

WITH(SYSTEM_VERSIONING = ON (HISTORY_TABLE = dbo.Countries_archive))

INSERT Countries (CountryName, Population) VALUES ('Neverland', 100)

UPDATE Countries SET Population = 101 WHERE CountryName = 'Neverland'

SELECT *, ValidFrom, ValidTo

FROM Countries

FOR SYSTEM_TIME ALL

ORDER BY ValidFrom

BEGIN TRAN

UPDATE Countries SET Population = 102 WHERE CountryName = 'Neverland'

WAITFOR DELAY '00:00:10'

UPDATE Countries SET Population = 103 WHERE CountryName = 'Neverland'

COMMIT TRAN

SELECT *, ValidFrom, ValidTo

FROM Countries

FOR SYSTEM_TIME ALL

ORDER BY ValidFrom

SELECT *

FROM countries_archive

DECLARE @local_time datetime2

,@utc_time datetime2

SET @local_time = '2018-07-04 13:40:00'

SET @utc_time = DATEADD(second, DATEDIFF(second, SYSDATETIME(), SYSUTCDATETIME()), @local_time)

SELECT *

FROM Countries

FOR SYSTEM_TIME AS OF @utc_time

DELETE FROM Countries_archive WHERE ValidTo <DATEADD(yy, -7, SYSUTCDATETIME())

ALTER TABLE Countries ADD Description varchar(100) NULL

UPDATE Countries SET Description = 'Not an actual country' WHERE CountryName = 'Neverland'

ALTER TABLE Countries DROP COLUMN Description

USE TestDB

IF EXISTS ( SELECT *

FROM sys.tables

WHERE name = 'Countries'

AND temporal_type_desc = 'SYSTEM_VERSIONED_TEMPORAL_TABLE')

BEGIN

ALTER TABLE Countries SET ( SYSTEM_VERSIONING = OFF)

END

DROP TABLE IF EXISTS Countries_archive

DROP TABLE IF EXISTS Countries

CREATE TABLE Countries (

CountryID int IDENTITY PRIMARY KEY NOT NULL

,CountryName varchar(50)

,Population int)

INSERT Countries (CountryName, Population) VALUES ('Neverland', 103)

CREATE TABLE Countries_archive (

CountryID int NOT NULL --no identity or primary key

,CountryName varchar(50)

,Population int)

ALTER TABLE Countries_archive ADD ValidFrom datetime2 NOT NULL

ALTER TABLE Countries_archive ADD ValidTo datetime2 NOT NULL

INSERT Countries_archive (CountryID, CountryName, Population, ValidFrom,ValidTo)

VALUES (1, 'Neverland', 100, '2011-01-01', '2012-01-01')

ALTER TABLE Countries ADD ValidFrom datetime2 NULL

ALTER TABLE Countries ADD ValidTo datetime2 NULL

UPDATE Countries SET ValidFrom = '2012-01-01'

UPDATE Countries SET ValidTo = '9999-12-31 23:59:59.9999999'

ALTER TABLE Countries ALTER COLUMN ValidFrom datetime2 NOT NULL

ALTER TABLE Countries ALTER COLUMN ValidTo datetime2 NOT NULL

ALTER TABLE Countries ADD PERIOD FOR SYSTEM_TIME (ValidFrom,ValidTo)

ALTER TABLE Countries SET (SYSTEM_VERSIONING = ON (HISTORY_TABLE = dbo.Countries_archive))

SELECT [2012].population - [2011].population AS 'population growth'

FROM Countries FOR SYSTEM_TIME AS OF '2011-01-01' AS [2011]

INNER JOIN Countries FOR SYSTEM_TIME AS OF '2012-01-01' AS [2012]

ON [2011].CountryID = [2012].CountryID

--Query and output JSON data

CREATE TABLE [dbo].[Employees](

[EmployeeID] [tinyint] IDENTITY(1,1) NOT NULL,

[FirstName] [varchar](100) NULL,

[LastName] [varchar](50) NULL,

[Address] [varchar](100) NULL,

[Employee_Number] [int] NULL

)

INSERT dbo.Employees (FirstName, LastName, Address)

VALUES ('Bob', 'Jackson', 'Under the bridge')

,('Bo', 'Didley', 'Home of mr. Bo Didley')

DECLARE @json NVARCHAR(MAX)

SET @json = '{"FirstName":"Bob"}'

SELECT ISJSON(@json) AS 'IsValidJSON?'

SELECT FirstName, lastname, address

FROM employees

WHERE EmployeeID = 1

FOR JSON AUTO

--Format query output as JSON

SELECT FirstName, lastname, address

FROM employees

WHERE EmployeeID in (1,2)

FOR JSON AUTO

SELECT FirstName, lastname, address

FROM employees

WHERE EmployeeID in (1,2)

FOR JSON PATH

SELECT FirstName, lastname, address

FROM employees

WHERE EmployeeID in (1,2)

FOR JSON PATH, ROOT ('Employees')

SELECT FirstName, lastname, address

FROM employees

WHERE EmployeeID in (1,2)

FOR JSON PATH, WITHOUT_ARRAY_WRAPPER

UPDATE Employees

SET Employee_Number = employeeID

WHERE EmployeeID = 1

SELECT FirstName, lastname, address, Employee_Number

FROM employees

WHERE EmployeeID in (1,2)

FOR JSON PATH, INCLUDE_NULL_VALUES

SELECT FirstName AS 'Name.FirstName'

, lastname AS 'Name.LastName'

, address

FROM employees

WHERE EmployeeID in (1,2)

FOR JSON PATH

--Extract data from JSON

DECLARE @json NVARCHAR(MAX)

SET @json = '{

"A null value":null

,"A text string":"string"

,"A number":2

,"A boolean (true or false)":true

,"A boolean (true or false)":false

,"An array":[1,2,3]

,"An object": {"key1":"value1", "key2":"value2"}

SELECT *

FROM OPENJSON(@json)

SELECT [key], value

FROM OPENJSON(@json)

WHERE type <> 0

SELECT [key], value

FROM OPENJSON(@json,'$."An object"')

SELECT [key], value

FROM OPENJSON(@json,'$."An array"')

SELECT [key], value

FROM OPENJSON(@json,'lax $."n array"')

SELECT [key], value

FROM OPENJSON(@json,'strict $."n array"')

SELECT *

FROM OPENJSON(@json)

WITH (

NameOfTheColumn bigint '$."A number"'

,NameOfTheOtherColumn varchar(100) '$."A text string"'

)

SELECT *

FROM OPENJSON(@json)

WITH (

NameOfTheColumn bigint '$."A number"'

,NameOfTheOtherColumn varchar(100) '$."A text string"'

,JSONColumn nvarchar(max) '$."An object"' AS JSON

,ObjectValue varchar(100) '$."An object".key1'

)

SELECT JSON_VALUE(@json, '$."A number"')

SELECT JSON_QUERY(@json, '$."An object"')

SELECT JSON_QUERY(@json, '$."A number"')

SELECT JSON_VALUE(@json, '$."An object"')

SELECT JSON_MODIFY(@json,'$."A number"', 17)

SELECT JSON_VALUE(@json, '$.Employees[1].address')

--Query and output XML data

DECLARE @xml XML

SET @XML = '<FirstName>Bob</Firstname>'

SELECT @xml

SELECT TRY_CAST('<FirstName>Bob</Firstname>' as XML)

SELECT EmployeeID as '@Id'

,FirstName

,LastName

FROM Employees

WHERE EmployeeID in (1,2)

FOR XML PATH ('Employee')

--Format query output as XML

SELECT EmployeeID

,FirstName

,LastName

FROM Employees

WHERE EmployeeID in (1,2)

FOR XML RAW

SELECT EmployeeID

,FirstName

,LastName

FROM Employees

WHERE EmployeeID in (1,2)

FOR XML RAW ('GiveThisElementAnotherName')

SELECT EmployeeID

,FirstName

,LastName

FROM Employees

WHERE EmployeeID in (1,2)

FOR XML RAW , ELEMENTS

SELECT EmployeeID

,FirstName

,LastName

,Employee_Number

FROM Employees

WHERE EmployeeID in (1,2)

FOR XML RAW

SELECT EmployeeID

,FirstName

,LastName

,Employee_Number

FROM Employees

WHERE EmployeeID in (1,2)

FOR XML RAW, ELEMENTS XSINIL

SELECT EmployeeID

,FirstName

,LastName

FROM Employees

WHERE EmployeeID in (1,2)

FOR XML RAW, ROOT ('Employees')

SELECT c.Customername, o.orderid, OrderDate

FROM sales.Orders o

INNER JOIN sales.Customers c on c.CustomerID = o.CustomerID

WHERE c.customerId in (832, 803)

AND YEAR(OrderDate)=2013

AND MONTH(OrderDate)=1

--ORDER BY OrderDate

FOR XML AUTO

SELECT EmployeeID as '@Id'

,FirstName

,LastName

FROM Employees

WHERE EmployeeID in (1,2)

FOR XML PATH ('Employee')

--outer query

SELECT c.CustomerID AS '@id'

,c.Customername

--subquery will be inserted here

FROM sales.customers c

WHERE c.customerId in (832, 803)

ORDER BY c.CustomerName

FOR XML PATH ('Customers'), ELEMENTS, ROOT ('CustomerOrders')

--subquery

SELECT o.orderid AS '@OrderID'

,o.OrderDate

FROM sales.customers c2

INNER JOIN sales.orders o on c2.CustomerID = o.CustomerID

WHERE c.customerID = c2.customerID

AND YEAR(OrderDate)=2013

AND MONTH(OrderDate)=1

FOR XML PATH('Orders'), ROOT('CustomerOrderId'),TYPE

--full query

SELECT c.CustomerID AS '@id'

,c.Customername

,(SELECT o.orderid AS '@OrderID'

,o.OrderDate

FROM sales.customers c2

INNER JOIN sales.orders o on c2.CustomerID = o.CustomerID

WHERE c.customerID = c2.customerID

AND YEAR(OrderDate)=2013

AND MONTH(OrderDate)=1

FOR XML PATH('Orders'), ROOT('CustomerOrderId'),TYPE)

FROM sales.customers c

WHERE c.customerId in (832, 803)

ORDER BY c.CustomerName

FOR XML PATH ('Customers'), ELEMENTS, ROOT ('CustomerOrders')

SELECT ol.orderlineId as '@OrderLineID'

,ol.Description

,ol.Quantity

FROM sales.orderlines ol

inner join sales.orders o2 on ol.OrderID = o2.OrderID

inner join sales.customers c3 on c3.CustomerID = o.CustomerID

WHERE o2.OrderID = o.orderid

FOR XML PATH ('OrderLines'), TYPE

DECLARE @xml varchar(1000)

DECLARE @xml_document_handle int

SET @xml = '

<Customername>Aakriti Byrraju</Customername>

</Customers>

<Customername>Bala Dixit</Customername>

</Customers>

</CustomerOrders>

-- Step 1

EXEC sp_xml_preparedocument @xml_document_handle OUTPUT, @xml;

--Step 2

SELECT *

FROM OPENXML (@xml_document_handle, '/CustomerOrders/Customers',11)

WITH ( id int,

Customername varchar(200));

--Step 3

EXEC sp_xml_removedocument @xml_document_handle

--XML output of customers, orders and order lines

SELECT c.CustomerID AS '@id'

,c.Customername

, (SELECT o.orderid AS '@OrderID'

,o.OrderDate

,(SELECT ol.orderlineId as '@OrderLineID'

,ol.Description

,ol.Quantity

FROM sales.orderlines ol

inner join sales.orders o2 on ol.OrderID = o2.OrderID

inner join sales.customers c3

on c3.CustomerID = o.CustomerID

WHERE o2.OrderID = o.orderid

for XML PATH ('OrderLines'), TYPE

)

FROM sales.customers c2

INNER JOIN sales.orders o on c2.CustomerID = o.CustomerID

WHERE c.customerID = c2.customerID

AND YEAR(OrderDate)=2013

AND MONTH(OrderDate)=1

FOR XML PATH('Orders'), ROOT('CustomerOrderId'),TYPE)

FROM sales.customers c

WHERE c.customerId in (832, 803)

ORDER BY c.CustomerName

FOR XML PATH ('Customers'), ELEMENTS, ROOT ('CustomerOrders')

DECLARE @xml varchar(max)

DECLARE @xml_document_handle int

SET @xml = '

<Customername>Aakriti Byrraju</Customername>

<Description>Ride on toy sedan car (Black) 1/12 scale</Description>

</OrderLines>

</Orders>

<Description>32 mm Double sided bubble wrap 50m</Description>

</OrderLines>

</Orders>

</CustomerOrderId>

</Customers>

<Customername>Bala Dixit</Customername>

<Description>Developer joke mug - old C developers never die (White)</Description>

</OrderLines>

<Description>USB food flash drive - chocolate bar</Description>

</OrderLines>

</Orders>

</CustomerOrderId>

</Customers>

</CustomerOrders>

-- Step 1

EXEC sp_xml_preparedocument @xml_document_handle OUTPUT, @xml;

--Step 2

SELECT *

FROM OPENXML (@xml_document_handle, '/CustomerOrders/Customers/CustomerOrderId/Orders/OrderLines',11)

WITH ( id int '../../../@id',

Customername varchar(1000) '../../../Customername',

OrderDate date '../OrderDate',

OrderID int '../@OrderID',

Description varchar(1000));

--Step 3

EXEC sp_xml_removedocument @xml_document_handle

--XQuery

SELECT @xml.query('/CustomerOrders/Customers/CustomerOrderId/Orders/OrderLines')

SELECT @xml.query('(/CustomerOrders/Customers/CustomerOrderId/Orders/OrderLines)[2]')

SELECT @xml.query('(/CustomerOrders/Customers[2]/CustomerOrderId/Orders/OrderLines)[2]')

SELECT @xml.query('(/CustomerOrders/Customers[@id=803]/CustomerOrderId/Orders/OrderLines)')

SELECT @xml.query('(/CustomerOrders/Customers[Customername="Bala Dixit"]/CustomerOrderId/Orders/OrderLines)')

--FLWOR

SELECT @xml.query('

for $Orders in /CustomerOrders/Customers/CustomerOrderId/Orders

return ($Orders)

SELECT @xml.query('

for $Orders in /CustomerOrders/Customers/CustomerOrderId/Orders

return string($Orders)

SELECT @xml.query('

for $Orders in /CustomerOrders/Customers/CustomerOrderId/Orders

let $Quantity :=$Orders/OrderLines/Quantity

where $Quantity > 20

return ($Orders)

SELECT @xml.query('

for $Orders in /CustomerOrders/Customers/CustomerOrderId/Orders

order by $Orders/@OrderID

return $Orders

--XQuery value

SELECT @xml.value('(/CustomerOrders/Customers[2]/CustomerOrderId/Orders/OrderLines)[1]', 'varchar(1000)')

SELECT @xml.value('(/CustomerOrders/Customers[2]/CustomerOrderId/Orders/OrderLines)[1]', 'int')

--XQuery exist

SELECT @xml.exist('(/CustomerOrders/Customers/CustomerOrderId/Orders/OrderLines)[5]')

SELECT @xml.exist('(/CustomerOrders/Customers[@id] = 832)')

--XQuery nodes

SELECT XML_table.value('../../../@id', N'int') as customerid

,XML_table.value('../../../Customername[1]', 'varchar(100)') as customername

,XML_table.value('../@OrderID', 'varchar(100)') as Orderid

,XML_table.value('@OrderLineID', 'varchar(100)') as OrderLineid

,XML_table.value('Quantity[1]', 'varchar(100)') as quantity

,XML_table.value('Description[1]', 'varchar(100)') as description

FROM @xml.nodes('/CustomerOrders/Customers/CustomerOrderId/Orders/OrderLines') as t(XML_table)

ORDER BY customerid desc

SELECT XML_table.value('../../@id', N'int') as customerid

,XML_table.value('@OrderID', N'int') as orderID

,XML_table.query('.') as orderdetails

FROM @xml.nodes('/CustomerOrders/Customers/CustomerOrderId/Orders') as t(XML_table)

--XQuery modify

DECLARE @xml XML

SET @xml = '

<LastName>Jackson</LastName>

</Employee>

<LastName>Didley</LastName>

</Employee>

</Employees>

SET @xml.modify('

insert attribute SSID {"idontknow"}

into (/Employees/Employee)[2]

SET @xml.modify('

insert <Employee Id="3"><FirstName>Jeff</FirstName><LastName>Williams</LastName></Employee>

after (/Employees/Employee)[2]

SET @xml.modify('

insert <Employee Id="3"><FirstName>Jeff</FirstName><LastName>Williams</LastName></Employee>

into (/Employees)[1]

--XQuery delete

SET @xml.modify('

delete /Employees/Employee[2]/@SSID

SET @xml.modify('

delete /Employees/Employee[2]/Address

If the element or attribute isn’t present, no error will be returned.

SET @xml.modify('

replace value of (/Employees/Employee[2]/@SSID)[1]

with "001-002-003"

SET @xml.modify('

replace value of (/Employees/Employee[2]/Address/text())[1]

with "Beverly Hills"

Code samples for my book on Querying data with Transact-SQL (MCSA 70-761), chapter 2

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