Declare a Transact-SQL variable
language-elementsAnalytics Platform System (PDW)
SQL analytics endpoint in
Microsoft Fabric
Warehouse in Microsoft Fabric
A Transact-SQL local variable is an object that can hold a single data value of a specific type.
You typically use variables in batches and scripts for the following purposes:
Use a variable as a counter to count the number of times a loop is performed, or to
control how many times the loop is performed.
Hold a data value to test by a control-of-flow statement.
Save a data value to return by a stored procedure return code or function return value.
The code samples in this article use the
or
sample
database, which you can download from the
Microsoft SQL Server Samples and Community
Projects
home page.
The names of some Transact-SQL system functions begin with two
at
signs (
). Although
earlier versions of SQL Server refer to the
functions as global variables,
functions aren’t
variables, and they don’t have the same behaviors as variables. The
functions are system
functions, and their syntax usage follows the rules for functions.
You can’t use variables in a view.
Changes to variables aren’t affected by the rollback of a transaction.
Use the
statement to initialize a Transact-SQL variable by:
Assigning a name. The name must start with a single
character.
Assigning a system-supplied or user-defined data type and a length. For numeric
variables, you can assign a precision and optional scale. For variables of type XML, you
can optionally assign a schema collection.
Setting the value to.
For example, the following
statement creates a local variable named
with
an
data type. By default, the value for this variable is.
AdventureWorks2025
AdventureWorksDW2025
@@@@@@@@DECLARE
@NULL
DECLARE
@mycounterNULL