MYSQL IN 与 EXISTS 的优化示例介绍

select  from A where id in (select id from B)
等价于:
for select id from B
for select  from A where A.id = B.id

select  from A where exists (select 1 from B where B.id = A.id)
等价于
for select  from A
for select  from B where B.id = A.id

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SELECT SQL_NO_CACHE  FROM rocky_member m WHERE EXISTS (SELECT 1 FROM rocky__appro a WHERE m.ID = a.user_id AND a.passed = 1);
/ 执行时间0.160s /
SELECT SQL_NO_CACHE  FROM rocky_member m WHERE m.ID in(SELECT ID FROM rocky__appro WHERE passed = 1);