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Stored proc Sort by Variable

kfenske
kfenske asked
on
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Last Modified: 2008-03-06
I would like to have a stored procedure result set sorted by  a field I pass to the procedure as a parameter.  I would also like to have the sort direction (asc/desc) determined by a parameter.  I believe that to make this work it must be in a precompiled procedure and must specify the field name and not the column number because I've read this in documentation.  I've tried every way I can think of and am wondering if I have to specify special pre-compile or binding rules on the procedure?

Here is my test code:

use pubs
go
drop proc kentest
go

create proc kentest (@vsort varchar(8)='au_lname')
as
select * from authors
order by @vsort

go
exec kentest @vsort='au_lname'

The error message I get is:
Msg 1008, Level 15, State 1
The select list item identified by the order by number '1' contains a variable as part of the expression that identifies a column position. Variables are only allowed when ordering by an expression referencing a column name.
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Commented:
The easiest way to do this is to write your procedure so that it constructs the whole SQL statement and then EXECs it. In your case:

CREATE PROC kentest (@vsort varchar(8)='au_lname')
AS

DECLARE @exestr varchar(255)
SELECT @exestr='select * from authors order by ' + @vsort
EXEC @exestr
GO

Of course, there is a small performance penalty since the @exestr has to be compiled every time the procedure is run.

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Commented:
Excellent answer!

Thanks
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