ELSE (IF...ELSE)

Imposes conditions on the execution of a Transact-SQL statement. The Transact-SQL statement (sql_statement) following the Boolean_expression is executed if the Boolean_expression evaluates to TRUE. The optional ELSE keyword is an alternate Transact-SQL statement that is executed when Boolean_expression evaluates to FALSE or NULL.

Syntax

IF Boolean_expression { sql_statement | statement_block }
[
    ELSE
    { sql_statement | statement_block } ]

Arguments

Boolean_expression

Is an expression that returns TRUE or FALSE. If the Boolean expression contains a SELECT statement, the SELECT statement must be enclosed in parentheses.

{sql_statement | statement_block}

Is any valid Transact-SQL statement or statement grouping as defined with a statement block. To define a statement block (batch), use the control-of-flow language keywords BEGIN and END. Although all Transact-SQL statements are valid within a BEGIN...END block, certain Transact-SQL statements should not be grouped together within the same batch (statement block).

Result Types

Boolean

Examples

This example produces a list of traditional cookbooks priced between $10 and $20 when one or more books meet these conditions. Otherwise, SQL Server prints a message that no books meet the condition and a list of traditional cookbooks that costs less than $10 is produced.

USE pubs
GO
DECLARE @msg varchar(255)
IF (SELECT COUNT(price)
   FROM titles 
   WHERE title_id LIKE 'TC%' AND price BETWEEN 10 AND 20) > 0
   
   BEGIN
     SET NOCOUNT ON
     SET @msg = 'There are several books that are a good value between $10 and $20. These books are: '
         PRINT @msg
      SELECT title 
     FROM titles 
     WHERE title_id LIKE 'TC%' AND price BETWEEN 10 AND 20
   END
ELSE
   BEGIN
     SET NOCOUNT ON
     SET @msg = 'There are no books between $10 and $20. You might consider the following books that are under $10.'
         PRINT @msg
     SELECT title 
     FROM titles 
     WHERE title_id LIKE 'TC%' AND price < 10       
   END

Here is the result set:

There are several books that are a good value between $10 and $20. These books are: 
title                                                                   
------------------------------------------------------------------------
Fifty Years in Buckingham Palace Kitchens
Sushi, Anyone?

(2 row(s) affected)

See Also

ALTER TRIGGER

Batches

Control-of-Flow Language

CREATE TRIGGER

IF...ELSE