Mysql Puzzle(Left Join)-Take out those department who have no employees assigned to it

EMP
EMPNO   ENAME    DEPTNO

DEPT
DEPTNO   DNAME

1st Way using Subquery

SELECT D.DNAME
FROM DEPT D
WHERE 

NOT EXISTS (SELECT * FROM EMP E WHERE D.DEPTNO = E.DEPTNO) 

2nd way using Left Join

SELECT D.DNAME
FROM DEPT D
LEFT JOIN EMP E ON D.DEPTNO = E.DEPTNO
WHERE E.DEPTNO IS NULL 

Mysql Joins

Joins are used to get data from Non Clustered indexes in a table

Following are the Types of Joins

Inner Join

id name       id  name
-- ----       --  ----
1  Pirate     1   Rutabaga
2  Monkey     2   Pirate
3  Ninja      3   Darth Vader
4  Spaghetti  4   Ninja

SELECT * FROM TableA
INNER JOIN TableB
ON TableA.name = TableB.name

id  name       id   name
--  ----       --   ----
1   Pirate     2    Pirate
3   Ninja      4    Ninja 

FULL OUTER JOIN

SELECT * FROM TableA
FULL OUTER JOIN TableB
ON TableA.name = TableB.name

id    name       id    name
--    ----       --    ----
1     Pirate     2     Pirate
2     Monkey     null  null
3     Ninja      4     Ninja
4     Spaghetti  null  null
null  null       1     Rutabaga       
null  null       3     Darth Vader

LEFT OUTER JOIN

SELECT * FROM TableA
LEFT OUTER JOIN TableB
ON TableA.name = TableB.name

id  name       id    name
--  ----       --    ----
1   Pirate     2     Pirate
2   Monkey     null  null
3   Ninja      4     Ninja
4   Spaghetti  null  null

RIGHT OUTER JOIN

SELECT * FROM TableA
RIGHT OUTER JOIN TableB
ON TableA.name = TableB.name

id  name       id    name
--  ----       --    ----

null  null     1     Rutabaga  

1   Pirate     2     Pirate

null  null     3     Darth Vader 

3   Ninja      4     Ninja