Hi, MARK!
On Aug 01, MARK CALLAGHAN wrote:
> Why does UNION ALL always use a temp table? It would be more
> efficient to send the result from each branch of a UNION ALL directly
> to the network rather than buffering it in a temp table first until
> all branches have been evaluated. Some apps use UNION ALL to improve
> performance by reducing round trips between the app and the server,
> but the use of a temp table in MySQL reduces the benefit of that.
No good reason. It would.
Regards / Mit vielen Grüßen,
Sergei
--
__ ___ ___ ____ __
/ |/ /_ __/ __/ __ \/ / Sergei Golubchik <serg@stripped>
/ /|_/ / // /\ \/ /_/ / /__ Principal Software Engineer/Server Architect
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