SQL语句效率优化--持续更新

1 delete与in搭配使用，效率特别低，如下可解决该问题，not in同理

/*正常写法*/
DELETE from activity where id in ( SELECT id from activity_data);

/*优化后写法*/
DELETE from activity where id in (select * from (SELECT id from activity_data) t);

原文地址：https://www.cnblogs.com/cdut-yy/p/12048130.html