in (select xxx)
优化前（用时0.8s）
update tb_statistics set count=count+1, created=now() where entity='User' and linked_id in (select action.user_id AS id from tb_action action where action.id=10686 and action.status=1) and linked_id<>1372 and (type = ('my_activity'));优化后（用时0.05s）
update tb_statistics, (select action.user_id AS id from tb_action action where action.id=10686 and action.status=1) AS b set count=count+1, created=now() where entity='User' and linked_id=b.id and linked_id<>1372 and (type = ('my_activity'));
优化说明：请不用使用in (select xxx)查询。