>> select a.col1, b.col2 from a,b
>> where a.col1 = b.col2
>> or a.col1 not in (select b.col2 from b)
>This would work, but it would be *much* slower than a UNION query. "Not
>In" queries are perhaps the slowest you can run; see the earlier thread
>"Query Problem" for a discussion. UNION queries are, in fact, very fast
>... just awkward to code and manipulate.
Why should this be slower since the UNION Query still has an identical not in clause?
This is far easier (for me) to read.
Marc