c2.execute("delete from entity_map where canon_id in (select canon_id from
entity_map_session where canon_id in (select canon_id from
entity_map_session group by canon_id having count(canon_id) < 10))")
delete entity_map2.*
from entity_map2
join (
select canon_id
from entity_map_session2
group by canon_id having count(canon_id) < 10
) a on a.canon_id = entity_map2.canon_id;
下一步应为“从表中删除”“使用联接”:
针对
entity_map_session2
表的子查询正在进行计数聚合,并且没有WHERE
或HAVING
子句,这意味着无法对其进行太多优化。但是,您可以删除其中一个不必要的嵌套子查询,例如使用:相关问题 更多 >
编程相关推荐