The
Employee
table holds all employees including their managers. Every employee has an Id, and there is also a column for the manager Id.
+----+-------+--------+-----------+ | Id | Name | Salary | ManagerId | +----+-------+--------+-----------+ | 1 | Joe | 70000 | 3 | | 2 | Henry | 80000 | 4 | | 3 | Sam | 60000 | NULL | | 4 | Max | 90000 | NULL | +----+-------+--------+-----------+
Given the
Employee
table, write a SQL query that finds out employees who earn more than their managers. For the above table, Joe is the only employee who earns more than his manager.
+----------+ | Employee | +----------+ | Joe | +----------+
Solution:
select E1.Name
from Employee as E1, Employee as E2
where E1.ManagerId = E2.Id and E1.Salary > E2.Salary
select e.Name as Employee
from Employee e, Employee m
where e.ManagerId is not NULL and
e.ManagerId = m.ID and e.Salary > m.Salary
select a.Name
from Employee a inner join Employee b on a.ManagerId=b.Id
where a.Salary>b.Salary
SELECT Name AS Employee FROM Employee e1
WHERE Salary > (SELECT Salary FROM Employee e2 WHERE e2.Id = e1.ManagerId)
SELECT e1.`Name`
FROM `Employee` e1
LEFT JOIN `Employee` e2 ON(e2.`Id` = e1.`ManagerId`)
WHERE e1.`ManagerId` IS NOT NULL AND e1.`Salary` > e2.`Salary`
