sql 拼写

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