Re: Subquery with range uses filesort

[David Marcus]

Rick,

Thank you.

I'm not sure the "(a,b) = (c,d)" is the problem since the query below
also uses a filesort. I don't know how to turn it into a join.
Currently, I'm using a temporary table (which works OK).

explain extended select * from Player
join History on HistoryPlayer = PlayerID and
HistoryDate =
( select HistoryDate
from History
where HistoryPlayer = PlayerID and HistoryDate <= '2013-01-01'
order by HistoryDate desc, HistoryDirector desc limit 0,1 )

id,select_type,table,type,possible_keys,key,key_len,ref,rows,filtered,Extra
1,PRIMARY,History,ALL,PlayerDateDirector,NULL,NULL,NULL,880850,100.00,
1,PRIMARY,Player,eq_ref,PRIMARY,PRIMARY,4,ratingscentral.History.HistoryPlayer,1,100.00,"Using where"
2,"DEPENDENT SUBQUERY",History,ref,PlayerDateDirector,PlayerDateDirector,4,ratingscentral.Player.PlayerID,8808,100.00,"Using where; Using index; Using filesort"