MySQL < 5.0 can only use 1 index per table. MySQL >= 5.0 can use more than one via an index merge. http://dev.mysql.com/doc/refman/5.0/en/index-merge-optimization.html On Sat, Sep 27, 2008 at 2:47 AM, Micah Gersten <micah@xxxxxxxxxxx> wrote: > MySQL queries use 1 index per table, so to speed the query, we need to > know what indices you have for the 2 tables. > > Thank you, > Micah Gersten > onShore Networks > Internal Developer > http://www.onshore.com > > > > Yves Sucaet wrote: > > Oh, sorry I forgot to mention this. It's a MySQL database. > > > > ----- Original Message ----- From: "Micah Gersten" <micah@xxxxxxxxxxx> > > To: "YVES SUCAET" <yves.sucaet@xxxxxxx> > > Cc: <php-db@xxxxxxxxxxxxx> > > Sent: Thursday, September 25, 2008 7:55 PM > > Subject: Re: query optimization > > > > > >> Other question is, what DB is this for? > >> > >> Thank you, > >> Micah Gersten > >> onShore Networks > >> Internal Developer > >> http://www.onshore.com > >> > >> > >> > >> YVES SUCAET wrote: > >>> How could I rewrite the following query so it runs faster: > >>> > >>> select distinct location from blockunit where blockid in ( > >>> select bu.blockid from blockunit bu inner join interactionparts ip on > >>> (bu.blockid = ip.part) > >>> where ip.blockid in > >>> > >>> > (110936,110937,111641,111642,113140,113141,114925,114926,121161,121162,124087, > >>> > >>> > >>> 124088,124562,124563,133358,133359,133409,133410,135304,135305,136096) > >>> union > >>> select bu.blockid from blockunit bu > >>> where bu.blockid in > >>> > >>> > (110936,110937,111641,111642,113140,113141,114925,114926,121161,121162,124087, > >>> > >>> > >>> 124088,124562,124563,133358,133359,133409,133410,135304,135305,136096) > >>> ) > >>> > >>> Thanks in advance, > >>> > >>> Yves > >>> > >>> > >>> > >>> > >> > > > > > > > > -- > PHP Database Mailing List (http://www.php.net/) > To unsubscribe, visit: http://www.php.net/unsub.php > >
