Hi there, I have trouble with a SQL statement that uses too much load on our server due to heavy traffic. MySQL uses temporary files and filesort, so I narrowed the problem down to this one here: TABLE A: ID INTEGER PRIMARY KEY TEXT VARCHAR(10) TABLE B: ID INTEGER PRIMARY KEY REF_ID INTEGER NUMBER FLOAT(7,2) No matter, how many entries I have in A and B and no matter what indexes I create, I always get a USING TEMPORARY, USING FILESORT when EXPLAINing the following simple statement: SELECT a.id, MIN(b.number) AS low FROM a JOIN b ON (a.id = b.ref_id) GROUP BY a.id ORDER BY low What can I do to speed up this query? I need to get a list of rows from table a with it's lowest reference number from table b. Thanks in advance, Marc
