【MySQL帮助】帮朋友优化SQL的过程--)从4S到0.011秒_MySQL

SELECT (op.cash_payment+op.pos_payment+op.online_payment+op.charge_card_payment) AS real_payment,op.* FROM db_order.`order_payment` AS op WHERE op.order_payment_id in (SELECT oi.order_payment_id FROM db_order.`order_info` AS oi WHERE oi.batch_order_id = '123456') ORDER BY op.insert_time DESC

SELECT   (op.cash_payment+op.pos_payment+op.online_payment+op.charge_card_payment) AS real_payment,op.*   FROM db_order.`order_payment` AS op,db_order.`order_info` oi WHERE op.order_payment_id=oi.order_payment_id and oi.batch_order_id = '123456'  ORDER BY op.insert_time DESC

发给朋友，朋友说相当快，在0.011S。

看来 这个IN确实需要谨慎使用，特别是在两表关联的时候，应该把in替换成内链接