一 概述
in()实例
select * from A where id in (select id from B);
exists()实例
select * from A where exists (selet 1 from B where A.id = B.id)
二 In()语句的工作原理
暂时总结到这里,待续
in()实例
select * from A where id in (select id from B);
exists()实例
select * from A where exists (selet 1 from B where A.id = B.id)
暂时总结到这里,待续