问题:想取结果在一些column在另一些column有咩有,做了两个test,发现结果一样。
use webforms
select * from NetworkAccountRequestInfo_old
where ReqLName not in (select lname from OnlineDirectoryFacultyStaffBanner) order by ReqLName
select ReqLName from NetworkAccountRequestInfo_old as a left join
OnlineDirectoryFacultyStaffBanner as b
on a.ReqLName = b.LName
where b.LName is null
order by ReqLName
select ReqLName from NetworkAccountRequestInfo_old order by ReqLName
select lname from OnlineDirectoryFacultyStaffBanner order by lname