Database Programming: User-Defined Functions And Linked Server Connections

This post addresses an edge-case programming issue, but if you've ever run into into it, this may be a useful trick to have in your back pocket.  This discussion applies to both SQL Server 2000 and SQL Server 2005; in SQL Server 2005, all databases involved must have SET TRUSTWORTHY ON run against them.

A colleague wished to call a user-defined function (UDF) housed on a linked server.  SQL Server does not allow cross-server calls to a user-defined function, so this call..

SELECT  String
FROM    OPENQUERY(ServerX, 'SELECT String FROM MDPGJan031Issue.dbo.ExplodeSet(''MEDPSDEV'')')

.. produces an error message.  The solution in this case is to place a stored procedure on ServerX that calls the UDF:

FROM    dbo.ExplodeSet ('MEDPSDEV')

.. and then call the stored procedure over the linked server connection:

SELECT  String
FROM    OPENQUERY(ServerX, 'EXEC MDPGJan031Issue.dbo.CallTheUDF')

This is a relatively simplistic example; you can also put the parameter to the UDF into a memory variable if you wish, which is certainly much more flexible.


Comments (3)

  1. Anonymous says:

    @Tom Stone: thanks for your comment, Tom.  I’m glad this helped you!

    Thanks for stopping by..


  2. Tom Stone says:


    This helped tremendously.

    I was trying to query sysobjects in a Sybase database using a linked server on a MS SQL Server database … and got the error "SELECT permission denied on column audflags of object sysobjects" even though the audflags column was not in my select clause.  Creating a Sybase stored procedure with "select name, id from sysobjects …" did the trick.

    Thanks again.


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