Hi

We have a number of Union queries that join two tables that have
guaranteed unique values. We currently use Union to merge them. Would
Union All provide better performance as it doesn't have to do any
checking for 'Distinctness'?

Rob Martin
Software Engineer

phone +64 03 377 0495
fax +64 03 377 0496
web www.chreos.com

Wild Software Ltd



Chad Z. Hower wrote:

>:: If you want duplicates, use "union all", otherwise you are
>:: getting distinct values.
>
>Aah - good point. :) Thanks for pointing that out, I'd totally forotten
>about that...
>
>
>