SUM Function - SQL
Overview
The SUM function in SQL calculates the total sum of a specified numeric column, aggregating all the values in that column. It is commonly used in SELECT statements to find the total of numeric data, optionally filtered by a condition.
Example:
SELECT
SUM(salary)
FROM
company.employees
WHERE
department_id = 1
Syntax:
SELECT
SUM(column_name)
FROM
table_name
[WHERE
condition]
This calculates the total sum of the values in column_name from table_name that meet the specified condition. In this syntax, the WHERE Statement is optional; if omitted, the SUM function will calculate the total for all rows in the table.
Sample Data:
| department_id | salary |
|---|---|
| 3 | 123000 |
| 2 | 135000 |
| 3 | 115000 |
| NULL | 115000 |
| 2 | 125000 |
| 1 | 120000 |
| 1 | 105000 |
| 5 | 200000 |
| 2 | 107000 |
| 1 | 100000 |
Example: Without the WHERE Statement
In this example, we are returning the sum of the salary column in the company.employees table. The final output is 1270000.
Example: With the WHERE Statement
In this example, we are returning the sum of the salary column in the company.employees table where the department_id column equals 1. The final output is 325000.
