Posted by ZeldorBlat on 07/26/07 13:18

On Jul 26, 2:14 am, FFMG <FFMG.2ub...@no-mx.httppoint.com> wrote:
> Hi,
>
> I was running a test on a table with 50000 rows.
> When I do:
>
> $sql = "SELECT * FROM TABLE";
> $result = mysql_query($sql);
> $total = mysql_num_rows(result);
>
> I get a 'run out of memory error', (the limit is set low on the test
> server).
>
> But when I do:
>
> $sql = "SELECT count(*) as num FROM TABLE";
> $result = mysql_query($sql);
> $result = mysql_fetch_assoc( $result );
> $total = $result['num'];
>
> Everything works fine.
>
> or is
> $sql = "SELECT FOUND_ROWS() AS num FROM TABLE";
> ..
> even better?
>
> So What is the 'preferred' method of getting a row count?
>
> FFMG
>
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Always use "select count(*)" for this type of thing.

The database doesn't necessarily need to go and actually get all the
rows to figure it out this way. If you "select *" and then ask for
the row count he actually needs to go get all those rows, which is why
you're running out of memory.

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