The IF ELSE statements are one of the most frequently used statement within SQL and control of
flow statements are one of the core statements within any programing language. Once you have
understood the concept you can easily make powerful scripts.
An IF statement is a check to see whether a condition is TRUE and is used in hundreds of different
scenarios such as checking whether an object exists, checking data for a value…… I always liken the
IF statement to checking your fridge for your favourite meal and if its there you eat otherwise you
check out all your other options.
The below is a simple script which tests to see whether I have the AdventureWorks2012 database.
IF EXISTS (SELECT * FROM sys.databases
WHERE name = 'AdventureWorks2012' )
PRINT 'AdventureWorks2012 is installed'
The result you will get is below.
AdventureWorks2012 is installed

The query checks whether the AdventureWorks2012 returns a value or is TRUE from my query and
then runs the PRINT command to confirm the value was returned as I expected.
You can make the IF statement more powerful by adding the ELSE statement. The ELSE Statement is
used as we often don’t just want to check if a statement is TRUE but also want to produce an action if its false.
DECLARE @TestValue int
SET @TestValue = 1
IF @TestValue >1
BEGIN
PRINT 'The Test value is greater than 1'
END
ELSE
PRINT 'The Test value is less than or equal to 1'
The result you will get is below.
The Test value is less than or equal to 1

Originally published at https://parvtheitgeek.com on January 14, 2015.