Mysql 单个表查询问题

Answer 1

select name from Employee where ManagerId !=null and salary>(select min(salary) from Employee where ManagerId =null);
这样写应该也可以。 可能我理解你的问题理解错了，我觉得我的语句的结果，和你的应该不一样！

Answer 2

select name from Employee t where 
    t.ManagerId is NOT NULL 
    AND 
    exists (
        select id from Employee a where   
        a.id = t.ManagerId 
        AND
        a.Salary < t.Salary 
    )

感觉都差不多...

Answer 3

找最高的

select max(Salary),ManagerId from Employee where ManagerId is not null

找全部的，如果索引包含ManagerId 可以在后面加上 ManagerId is not null缩小范围

select * from Employee where Salary>(select max(Salary) from Employee where ManagerId is null)