Posted by Erland Sommarskog on 09/27/25 11:35

(JLavalley@Enlighten.Net) writes:
> Can someone explain to me why the following doesn't work?
>
> declare @oname sysname
> select @oname=name from sysobjects where name like
> "df__mytable__mycol%"
>
> alter table mytable drop constraint @oname

Why should it work? There are some places you can use variables in
T-SQL for object names, but in most places you can't. Check out the
syntax chart in Books Online when in doubt.

You can use dynamic SQL: EXEC('ALTER TABLE tbl DROP CONSTRAINT ' + @oname)

For more information about dynamic SQL, see this article on my web site:
http://www.sommarskog.se/dynamic_sql.html.

--
Erland Sommarskog, SQL Server MVP, esquel@sommarskog.se

Books Online for SQL Server 2005 at
http://www.microsoft.com/technet/prodtechnol/sql/2005/downloads/books.mspx
Books Online for SQL Server 2000 at
http://www.microsoft.com/sql/prodinfo/previousversions/books.mspx

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