SELECT @local_variable (Transact-SQL)

Specifies that the specified local variable that is created by using DECLARE **@**local_variable should be set to the specified expression.

For assigning variables, we recommend that you use SET **@**local_variable instead of SELECT **@**local_variable. For more information, see SET @local\_variable.

Transact-SQL Syntax Conventions

Syntax

SELECT { @local_variable = expression } [ ,...n ] [ ; ]

Arguments

• **@**local_variable
  Is a declared variable for which a value is to be assigned.

• expression
  Is any valid expression. This includes a scalar subquery.

Remarks

SELECT @local_variable is typically used to return a single value into the variable. However, when expression is the name of a column, it can return multiple values. If the SELECT statement returns more than one value, the variable is assigned the last value that is returned.

If the SELECT statement returns no rows, the variable retains its present value. If expression is a scalar subquery that returns no value, the variable is set to NULL.

One SELECT statement can initialize multiple local variables.

Examples

A. Using SELECT @local\_variable to return a single value

In the following example, the variable @var1 is assigned Generic Name as its value. The query against the Store table returns no rows because the value specified for CustomerID does not exist in the table. The variable retains the Generic Name value.

USE AdventureWorks ;       
GO       
DECLARE @var1 nvarchar(30);       
SELECT @var1 = 'Generic Name';       
SELECT @var1 = Name       
FROM Sales.Store       
WHERE CustomerID = 1000 ;      
SELECT @var1 AS 'Company Name';

Here is the result set.

Company Name                  
------------------------------
Generic Name                  

B. Using SELECT @local\_variable to no result set returns null

In the following example, a subquery is used to assign a value to @var1. Because the value requested for CustomerID does not exist, the subquery returns no value and the variable is set to NULL.

USE AdventureWorks ; 
GO 
DECLARE @var1 nvarchar(30) 
SELECT @var1 = 'Generic Name' 
SELECT @var1 = (SELECT Name 
FROM Sales.Store 
WHERE CustomerID = 1000) 
SELECT @var1 AS 'Company Name' ;

Here is the result set.

Company Name
----------------------------
NULL

See Also

Reference

DECLARE @local\_variable (Transact-SQL)
Expressions (Transact-SQL)
SELECT (Transact-SQL)

Help and Information

Getting SQL Server 2005 Assistance