in mysql sub queries dont perform well. You can could try this
SELECT a.ID FROM ven_tes a, ven_tes b where a.id=b.id and b.id_ven=6573 . On 5/20/08, Wakan <[EMAIL PROTECTED]> wrote: > > Hi, > can someone could explain where are problems in this query: > > EXPLAIN > SELECT ID > FROM ven_tes > WHERE ID IN (SELECT ID FROM ven_tes WHERE ID_ven=6573) > +----+--------------------+---------+-----------------+----------------+---------+---------+------+------+--------------------------+ > > > | id | select_type | table | type | possible_keys | > key | key_len | ref | rows | Extra | > +----+--------------------+---------+-----------------+----------------+---------+---------+------+------+--------------------------+ > > > | 1 | PRIMARY | ven_tes | index | NULL | > PRIMARY | 4 | NULL | 6573 | Using where; Using index | > | 2 | DEPENDENT SUBQUERY | ven_tes | unique_subquery | PRIMARY,ID_ven | > PRIMARY | 4 | func | 1 | Using index; Using where | > +----+--------------------+---------+-----------------+----------------+---------+---------+------+------+--------------------------+ > > > as you can see, it doesn't use absolutely indexes on ven_tes (ID is the > primary key, ID_ven is index) > > Thanks in advance > Carlo > > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] > >
