<pre><code>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))")
</code></pre>
<p>我想加快上述操作的速度。特别是我们删除行的最后一个。最好的方法是什么</p>
<p>下一步应为“从表中删除”“使用联接”:</p>
<pre><code>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;
</code></pre>