Posted by Erland Sommarskog on 02/05/06 12:09

Tony Rogerson (tonyrogerson@sqlserverfaq.com) writes:
> create proc myproc
> @optional_parm1 int = NULL,
> @optional_parm2 int = NULL
> begin
> if @optional_param1 is not null and @optional_param2 is not null
> select max( blah )
> from yourquery (or view)
> where col1 = @optional_parm1
> and col2 = @optional_parm2
> else if @optional_param1 is not null
> select max( blah )
> from yourquery (or view)
> where col1 = @optional_parm1
> else if @optional_parm2 is not null
> select max( blah )
> from yourquery (or view)
> where col2 = @optional_parm2
> else
> select max( blah )
> from yourquery (or view)
>
> end
>
> While the above does contain logic, it will give you the best plan in MS
> SQL Server,


Maybe. Keep in mind that SQL Server employs parameter sniffing, so if
you first call the procedure with NULL in the input parameters, all
the SELECT:s will be optimized for NULL, which may not give the best
plan.


--
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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