SQL MAX function

MAX function returns the maximum from the expression. It is an example of aggregate functions.

Syntax:

select max(column_name) from table_name;

Examples:-

Consider below EMP table structure

Empno	Empname	Salary	Deptno
10	Bill	12000	5
11	Solomon	10000	5
12	Susan	10000	5
13	Wendy	9000	1
14	Benjamin	7500	1
15	Tom	7600	1
16	Henry	8500	2
17	Robert	9500	2
18	Paul	7700	2

1. Find the highest salary among the employees.

select max(salary) from EMP;     

MAX(SALARY)

------------------------

      12000

2. Find the highest salary among the employees in a department (Using where clause). 

select max(salary) from EMP where deptno = 1;     

MAX(SALARY)

------------------------

      9000

3. Find the highest salary in each department (Using group by clause). 

select deptno,max(salary) from EMP group by deptno;     

 DEPTNO  MAX(SALARY)

 ----------     -----------

1               9000

2               9500

5               12000