Transact SQL 101 - Lesson 12_SQL.txt

--Example 1
--Declare Variable; Do Not Assign Value
DECLARE @TestVar varchar(25)
SELECT @TestVar --Variable Initialized and value is NULL

--Declare and Assign Value to Variable
DECLARE @TestVar varchar(25)
SET @TestVar = 'Some String Value'
SELECT @TestVar --Variable is assigned value specified

--Example 2
DECLARE @StateProvince nvarchar(50), @City nvarchar(30) --Declare Variable
SET @StateProvince = 'Texas' --Assign Value
SET @City = 'Dallas' --Assign Value

SELECT * FROM saleslt.address
WHERE StateProvince = @StateProvince
AND City = @City

--Example 3
--Use Variables to INSERT Data
DECLARE @AddressLine1 nvarchar(50), @City nvarchar(30), @State nvarchar(50)
SET @AddressLine1 = '123 Main Street'
SET @City = 'Dallas'
SET @State = 'TX'

INSERT INTO saleslt.address
		(AddressLine1, City, StateProvince, CountryRegion, PostalCode)
VALUES (@AddressLine1, @City, @State, 'United States','75004')

SELECT * FROM saleslt.address

--Example 4
--Using Function to assign value
DECLARE @CurrentDate smalldatetime
SET @CurrentDate = GETDATE()
PRINT @CurrentDate

--Example 5
--Use a SELECT statement to assign value 
DECLARE @MaxTotal money
SET @MaxTotal = (SELECT MAX(totaldue) FROM saleslt.salesorderheader) 
PRINT @MaxTotal