title: How to select the max salary per department, including the employees that earn it
body: <p>Given a table <code>Employees</code></p>
  
  <pre><code>+-------+--------+-----------+------+-----------+------+------+--------+
  | EMPNO | ENAME  |    JOB    | MGR  | HIREDATE  | SAL  | COMM | DEPTNO |
  +-------+--------+-----------+------+-----------+------+------+--------+
  |  7369 | SMITH  | CLERK     | 7902 | 17-Dec-80 |  800 |      |     20 |
  |  7499 | ALLEN  | SALESMAN  | 7698 | 20-Feb-81 | 1600 |  300 |     30 |
  |  7521 | WARD   | SALESMAN  | 7698 | 22-Feb-81 | 1250 |  500 |     30 |
  |  7566 | JONES  | MANAGER   | 7839 | 02-Apr-81 | 2975 |      |     20 |
  |  7654 | MARTIN | SALESMAN  | 7698 | 28-Sep-81 | 1250 | 1400 |     30 |
  |  7698 | BLAKE  | MANAGER   | 7839 | 01-May-81 | 2850 |      |     30 |
  |  7782 | CLARK  | MANAGER   | 7839 | 09-Jun-81 | 2450 |      |     10 |
  |  7788 | SCOTT  | ANALYST   | 7566 | 19-Apr-87 | 3000 |      |     20 |
  |  7839 | KING   | PRESIDENT | null | 17-Nov-81 | 5000 |      |     10 |
  |  7844 | TURNER | SALESMAN  | 7698 | 08-Sep-81 | 1500 |    0 |     30 |
  |  7876 | ADAMS  | CLERK     | 7788 | 23-May-87 | 1100 |      |     20 |
  |  7900 | JAMES  | CLERK     | 7698 | 03-Dec-81 |  950 |      |     30 |
  |  7902 | FORD   | ANALYST   | 7566 | 03-Dec-81 | 3000 |      |     20 |
  |  7934 | MILLER | CLERK     | 7782 | 23-Jan-82 | 1300 |      |     10 |
  +-------+--------+-----------+------+-----------+------+------+--------+
  </code></pre>
  
  <p>And another table <code>Departments</code></p>
  
  <pre><code>+--------+------------+----------+
  | DEPTNO |   DNAME    |   LOC    |
  +--------+------------+----------+
  |     10 | ACCOUNTING | NEW YORK |
  |     20 | RESEARCH   | DALLAS   |
  |     30 | SALES      | CHICAGO  |
  |     40 | OPERATIONS | BOSTON   |
  +--------+------------+----------+
  </code></pre>
  
  <p>How can I find the maximum salary of each department?</p>
  
  <p>The output format line is:</p>
  
  <pre><code>DEPTNO,ENAME,DNAME,SAL,LOC
  </code></pre>