Re: LIKE and indexes?

From: Alexander Jerusalem <alexander(dot)jerusalem(at)pop(dot)chello(dot)at>
To: adb <adb(at)Beast(dot)COM>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: LIKE and indexes?
Date: 2001-03-15 01:39:27
Message-ID: 4.3.2.7.0.20010315023628.00cf9100@pop.chello.at
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Thanks for your answer, Alex!

I've done an EXPLAIN and I saw that no index was used although my SQL
statement had a wild card only at the end as you pointed out ('blah%'). My
guess is that this is because of the locale support.

Regards,
Alexander Jerusalem

At 01:22 15.03.01, adb wrote:
>When in doubt, try the explain command
>
>Not exactly sure about postgres but in general LIKE can
>only use an index in the case of LIKE "Something%"
>
>LIKE "%Something" or LIKE "%Something%"
>won't use an index since it would have to scan the entire
>index to find all matches.
>
>Alex.
>
>
>
>On Wed, 14 Mar 2001, Alexander Jerusalem wrote:
>
> > Hi,
> >
> > Can anyone telle me if and when a LIKE query uses an index? I've compiled
> > postgres with locale support. Does that have any influence indexes?
> >
> > thanks,
> >
> > Alexander Jerusalem
> >
> >
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