Re: Subquery taking too much time on 5.5.18?

[Cabbar Duzayak]

Hmm,

Looking at the link http://www.artfulsoftware.com/infotree/queries.php
and explanations here, EXISTS() should have performed better, but does
not seem to??? I stopped it after about 5 minutes.

I tried both:

  SELECT * FROM A WHERE EXISTS (SELECT * FROM B WHERE A.id=B.A_ID and
B.name like 'X%');

and

  SELECT * FROM A WHERE EXISTS (SELECT B.A_ID FROM B WHERE A.id=B.A_ID
and B.name like 'X%');

Both are slow...


On Sat, Jul 7, 2012 at 8:34 AM, Rik Wasmus <rik@stripped> wrote:
>> See "The unbearable slowness of IN()" at
>> http://www.artfulsoftware.com/infotree/queries.php
>
>
> Do you read your own links? Excerpt:
>
>> In 5.0, EXISTS() is much faster than IN(), but slower than JOIN. In 5.5,
> EXISTS() performs about as well as JOIN.
>
> So.... judging by the subject line...
>
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