select A from weekreport where A in (select B from user1)--B与A的交集select B from user1 where B in (select A from weekreport)--B与A的交集结果应该一样的
select mobilenumber from weekreport where mobilenumber in (select mobile from user1)select mobile from user1 where mobile in (select mobilenumber from weekreport) 以上两句是不一样的。我猜你的意思要以下语句: Select W.MobileNumber From WeekReport W Inner Join user1 U On w.MobileNumber =U.Mobile
而另一个正好相反
另一个是从user1里面取记录(条件是mobile包含在(select mobilenumber ...)里面这个有什么不同吗?
子查询优先级最高,你的where条件是在子查询执行后得到的结果中查找条件符合的记录啊~
自己再好好琢磨琢磨吧
where A in (select B from user1)--B与A的交集select B from user1 where
B in (select A from weekreport)--B与A的交集结果应该一样的
where mobilenumber in (select mobile from user1)select mobile from user1 where
mobile in (select mobilenumber from weekreport)
以上两句是不一样的。我猜你的意思要以下语句:
Select W.MobileNumber From WeekReport W Inner Join user1 U On w.MobileNumber =U.Mobile
"weekreport表中的记录比user1中的多得多"