Re: Puzzled: why does join run 27,252 x faster than left outer join?

[KimSeong Loh]

Looks like not the table order, the difference is the Range checked for each record (index map: 1)

I guess the LEFT join should be able to use the same optimisation as well, but why it doesn't.

Can you try using IN for both the inner and left join as well

mysql> explain select sum(b.amount)*-1
-> from lockbox a left outer join ledger b
-> on b.tranid in (a.payid, a.secid, a.petid)\G;