Re: rewrite in to exists?

On Thu, 18 Sep 2003 13:23:37 +0800, "Christopher Kings-Lynne"
<snip>

>To the original poster: You did not provide a lot of information, but
>the following suggestions might give you an idea ...
<snip>
>

Yes, sorry about that. But in my query for a set of dates returned from the subquery I would then like to get all records that match this set of dates (ordered).

I believe this query will work and hopefully speed it up (the "IN" query is extremely slow)...I give this one a try:

>SELECT t1.code, t1.id, t1.date_of_service
> FROM tbl t1 INNER JOIN
> (SELECT DISTINCT date_of_service
> FROM tbl
> WHERE xxx >= '29800' AND xxx <= '29909'
> AND code = 'XX'
> ) AS t2 ON (t1.date_of_service = t2.date_of_service)
> WHERE t1.client_code = 'XX'
> ORDER BY id, date_of_service;

A question I have is is the "DISTINCT" really going to help or is it just going to throw another sort into the mix making it slower?

Thanks for the help!

Laurette