mysql的从另外一张表update多个字段到另外一张表中去
例如: 把表?tk_zyt_scenery_order的 字段更新到?t_advs_order中去, 一般可能会这样写:
?
UPDATE t_advs_order ?SET?
attribute1=(SELECT o.order_state FROM tk_zyt_scenery_order o WHERE o.order_id=`on`),
attribute2=(SELECT o.order_state FROM tk_zyt_scenery_order o WHERE o.order_id=`on`)
WHERE EXISTS (SELECT o.order_state FROM tk_zyt_scenery_order o WHERE o.order_id=`on`);
?
这样效率比较低下, 优化写法:
?
UPDATE t_advs_order a INNER JOIN tk_zyt_scenery_order s ON s.order_id=a.`on` SET?
a.attribute1=s.order_id,
a.attribute2=s.order_id;
?
