Shashank Tripathi wrote:
>> select something from othertable;
>> select * from table where table_id in (?, ?, ?, ?, ?, ?, ?, ...)
>
>
> This is what MySQL's CEO Martin said in an interview on Slashdot. If
> we can manage two queries as above through, say, a PHP application,
> with each executing in 0.004 seconds, then an optimized subquery needs
> to be beat the 0.008 mark to be a viable alternative.
Not really.
If you have too many values, you have problems.. eg the "select
something from table" returns 100+ records (for example, don't have a
concrete number), you'll run into this problem:
http://dev.mysql.com/doc/refman/4.1/en/packet-too-large.html
when you try to put them all in the 'in' clause in the 2nd query.
But as you say not usually a problem in most cases but something you
need to be aware of (and you're only aware of it once you've been bitten
by it heh).
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