Re: Query Help using Except

On Thu, Oct 23, 2003 at 14:17:08 -0400,
yusuf0478(at)netscape(dot)net wrote:
>
> I can't do the following, since the number of selected columns have to match:

One option is to use where NOT EXISTS instead of EXCEPT. Another way would
be to add A.id to the rows in the set difference using a join. I expect the
second method would be slower and that you should try using NOT EXISTS.

>
> select A.id
> , A.charge
> , B.user_id
> , C.employee_id
> from A
> inner join B using (user_id)
> inner join C using (employee_id)
>
> except
>
> select X.charge
> , Y.user_id
> , Z.employee_id
> from X
> inner join Y using (user_id)
> inner join Z using (employee_id)