Re: question about performance

am  Sun, dem 20.07.2008, um 20:08:21 +0200 mailte Robert Urban folgendes:
> Hi PostgreSQLer,
>
> if I have a table, the_table, with a DATE field, i'll call it 'day', and
> I'd like to find all rows whos day falls within a given month, which of the
> following methods is faster/costs less:
>
> 1.
>
>     SELECT * FROM the_table WHERE day LIKE '2008-01-%';
>
> 2.
>
>     SELECT * FROM the_table
>         WHERE ( day BETWEEN '$month_begin' AND '$month_end' );
>
>     # where $month_begin is '2008-01-01' and $month_end is '2008-01-31';

Probably the second one, but it depends if you have a propper index.

Other solution: create a functional index based on date_trunc and
rewrite your where-condition also.

Andreas
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Andreas Kretschmer
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