users表有 ,UserPoint表没有
1,SELECT COUNT(1) FROM users(nolock) left join UserPoint(nolock) on users.UserID=UserPoint.UserID
where Userpoint.UserID IS NULL
2,SELECT COUNT(UserID) FROM users WHERE userid NOT In (SELECT userid FROM UserPoint)
性能问题
3,SELECT COUNT(UserID) FROM users u WHERE Not
EXISTS (SELECT UserID FROM UserPoint up WHERE u.UserID=up.UserID)
由于垃圾数据3查询数据多余2,因为在UserPoint 表中有垃圾数据