SUM function returns the sum of the expression. It is an example of aggregate functions.

Syntax:

select sum(column_name) from table_name;

SUM can be done with the numeric values only.

Examples:-

Consider below EMP table structure

 EMPNNO EMPNAME SALARY DEPTNO 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 19 Dora 8500 3 20 Samuel 6900 3 21 Mary 7500 3 22 Daniel 6500 4 23 Ricardo 7800 4 24 Mark 7200 4

1. Find the sum of salary for all employees.

select sum(salary) from EMP;
SUM(SALARY)
————————
126200
2. Find the sum of salary of the employees in a department (Using where clause).
select sum(salary) from EMP where deptno = 1;
SUM(SALARY)
————————
24100
3. SUM cannot be used with non-numeric columns
select sum(empname) from emp;
*
ERROR at line 1:
ORA-01722: invalid number
4) SUM of salaries of employees in each (Using group by)
select deptno,sum(salary) from emp group by deptno;
DEPTNO SUM(SALARY)
———-   ———–
1              24100
2              25700
5              32000
4              21500
3              22900
5) SUM with dual table.
select sum(3+5) from dual;
SUM(3+5)
———-
8