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Pass a variable to a linked server query

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This article describes how to pass a variable to a linked server query.

Original product version:   SQL Server Books Online
Original KB number:   314520

Summary

When you query a linked server, you frequently perform a pass-through query that uses the OPENQUERY, OPENROWSET, or OPENDATASOURCE statement. You can view the examples in SQL Server Books Online to see how to do this by using pre-defined Transact-SQL strings, but there are no examples of how to pass a variable to these functions. This article provides three examples of how to pass a variable to a linked server query.

To pass a variable to one of the pass-through functions, you must build a dynamic query.

Any data that includes quotes needs particular handling.

Pass basic values

When the basic Transact-SQL statement is known, but you have to pass in one or more specific values, use code that is similar to the following sample:

DECLARE @TSQL varchar(8000), @VAR char(2)
SELECT @VAR = 'CA'
SELECT @TSQL = 'SELECT * FROM OPENQUERY(MyLinkedServer,''SELECT * FROM pubs.dbo.authors WHERE state = ''''' + @VAR + ''''''')'
EXEC (@TSQL)

Pass the whole query

When you have to pass in the whole Transact-SQL query or the name of the linked server (or both), use code that is similar to the following sample:

DECLARE @OPENQUERY nvarchar(4000), @TSQL nvarchar(4000), @LinkedServer nvarchar(4000)
SET @LinkedServer = 'MyLinkedServer'
SET @OPENQUERY = 'SELECT * FROM OPENQUERY('+ @LinkedServer + ','''
SET @TSQL = 'SELECT au_lname, au_id FROM pubs..authors'')'
EXEC (@OPENQUERY+@TSQL)

Use the Sp_executesql stored procedure

To avoid the multi-layered quotes, use code that is similar to the following sample:

DECLARE @VAR char(2)
SELECT @VAR = 'CA'
EXEC MyLinkedServer.master.dbo.sp_executesql
N'SELECT * FROM pubs.dbo.authors WHERE state = @state',
N'@state char(2)',
@VAR

See Also

For more information, see the following topics: