SUM (SQL)
SUM (SQL) function is used to return a total on the values of a column for a group of rows. The SUM (SQL) function adds up all the values for the expression passed to it as an argument, either a column name or the result of a calculation. The value of an argument must be numeric to use the SUM (SQL) function. The SUM (SQL) function cannot be used on columns having a data type other than numeric, such as character or date.
The basic syntax is as follows:
SUM (expression_or_column_to_be_added)
Example 1:
The following SUM SQL will return total amount of salary paid to employees
SELECT sum(salary) FROM employee;
Output:
Example 2:
The following query will return total employee salary for each department:
SELECT deptno, sum(salary)
FROM employee
GROUP BY deptno;
Output:
