Re: Pattern matching ints

From: Albe Laurenz <laurenz(dot)albe(at)wien(dot)gv(dot)at>
To: "Tim Smith *EXTERN*" <randomdev4+postgres(at)gmail(dot)com>, pgsql-general <pgsql-general(at)postgresql(dot)org>
Subject: Re: Pattern matching ints
Date: 2015-01-26 12:51:36
Message-ID: A737B7A37273E048B164557ADEF4A58B365928EA@ntex2010i.host.magwien.gv.at
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Tim Smith wrote:
> Is there a more efficient way to pattern match integer columns other
> than something like :
>
> where cast(mynumber as text) ~ '.*123.*'
>
>
> I also seem to recall you can't create indexes on casts either ?

I don't think you can do this without converting the column to a string.

I guess that you can create an index if the cast function is immutable;
at any rate you can create an index on intcolumn::text.

But such an index would not help you with a query like the one you
show above. The only thing that could speed up such a query would
be a trigram index on the string representation of the value.

Yours,
Laurenz Albe

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