Re: quickest query to check a table for existance of a value in a field

From: chester c young <chestercyoung(at)yahoo(dot)com>
To: me(at)shanewright(dot)co(dot)uk
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: quickest query to check a table for existance of a value in a field
Date: 2002-03-25 21:41:12
Message-ID: 20020325214112.27370.qmail@web12705.mail.yahoo.com
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> I want a quick way to find out if there are any rows matching a
> specified value for this indexed field. I dont care how many there
> are or what their properties are, just if there are any or not.
>
> SELECT COUNT(c2) AS num FROM mytable WHERE c2=1234;
>
> Thanks
> Shane

Try: select 1 as yes from mytable where c2=1234 limit 1;
or: select 1 as yes where exists( select 1 from mytable where c2=1234
);

would be interesting to see differences in performance on your data

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