无详细内容 无 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
<无详细内容> <无> $velocityCount-->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;