Question

I want to create a function in SQL Server 2005 that returns a table which the query is passing from my program…

But when I create that function with this script:

CREATE FUNCTION fn_test (@source varchar(255))  
RETURNS TABLE AS  
RETURN
    EXECUTE (@source)

The script is showing error message

Incorrect syntax near the keyword “EXECUTE`

Answer 1

It’s perfectly correct – you’re not allowed to execute arbitrary SQL as part of an inline table valued function:

--Transact-SQL Inline Table-Valued Function Syntax 
CREATE FUNCTION [ schema_name. ] function_name 
( [ { @parameter_name [ AS ] [ type_schema_name. ] parameter_data_type 
    [ = default ] [ READONLY ] } 
    [ ,...n ]
  ]
)
RETURNS TABLE
    [ WITH <function_option> [ ,...n ] ]
    [ AS ]
    RETURN [ ( ] select_stmt [ ) ]
[ ; ]

If you need(*) to have a facility to pass arbitrary SQL into a SQL Server object and have it execute it, use a stored procedure rather than a function. Functions are not meant to alter the state of the database, but arbitrary SQL can do… arbitrary things.

---

(*)You don’t.

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As a procedure, it would be:

CREATE PROCEDURE test (@source varchar(255))  
AS
    EXECUTE (@source)

But as is probably evident at this point – if you want to execute arbitrary SQL stored as strings, you may as well just directly call EXECUTE on them. That’s part of what I was alluding to when I put my (*) in. The other part is – why send it in a string variable to the server at all – why not just send the SQL you want to execute, if you’re going to run arbitrary SQL on the server anyway.