mysql 5.6 inner join and 慢优化

慢示例: SELECT o.id FROM o_schoolnotice o INNER JOIN

o_schoolnotice_parent p ON o.id = p.noticeid AND p.parenttype = 3 AND p.parentid = 129137

WHERE o.state = '1' AND p.state = '3'

执行需要1秒以上

快示例: SELECT o.id

FROM(

select id, noticeid, state

from o_schoolnotice_parent

where parenttype= '3'

and parentid= 129137) p

INNER JOIN o_schoolnotice o ON o.id= p.noticeid

WHERE o.state= '1'

AND p.state= '3'

执行只需要0.2秒

mysql 5.6 版本对于inner join 后面接and条件优化效果不好，请将and条件改为子查询。