Yep - seems to work - Thanks!

>If you keep this up, we're going to send you a bill <s>.
>
>This is a situation for a CROSS JOIN.
>
>(Warning - this is straight off the top of my head)
>
>SELECT x.a, x.b
>FROM
> (SELECT a.value, b.value FROM a CROSS JOIN b) AS x
> LEFT OUTER JOIN j ON x.a = j.a_value AND x.b = j.b_value
>WHERE
> j.id IS NULL
>
>You can play with removing the derived table.
>
>-Mike