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Re: Count two tables with duplicate check

From: Geoff Muldoon <geoff.muldoon_at_trap.gmail.com>
Date: Wed, 14 Sep 2005 11:28:09 +1000
Message-ID: <MPG.1d9227b776ee0c259896ee@news.readfreenews.net> 





MHakimjavadi_at_gmail.com says...



> I need to count the number record in two tables with duplicate check,

> so I have:




> Select (DISTINCT AAA) from

>   (Select emp_num AAA from A

>    union all

>    Select emp_num AAA from B)

> 

> and it is working fine but very slow. Please advice.




Look up the difference between "union all" and just "union".



G
Received on Tue Sep 13 2005 - 20:28:09 CDT












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