MySQL COUNT(), AVG() and SUM() Functions

In this tutorial we will learn about the count(), avg() and sum() functions

Assume the table employee with the following data to which we will perform these function.

COUNT() function

The COUNT function is used to retrieve the number of rows that satisfies the specified criteria.

Syntax for COUNT() function

SELECT COUNT(*)
FROM table_name
WHERE condition;

Example

select count(*) as IndianCount from employee
where location='India';

Output

In the above query, we have used alias name IndianCount for the column label to be returned.
The query will return the count of employees who belong to location India.

SUM() function

The SUM function will return the sum of a column whose datatype is number or integer.

Syntax for SUM() function

SELECT SUM(column_name)
FROM table_name
WHERE condition;

Example

SELECT SUM(salary) as TotalSalary
FROM employee
WHERE location='India';

Output

The above query will return the total sum of the salary column whose location is India.

AVG() Function

The AVG function is used to return the average value of a column whose type is numeric.

Syntax for AVG() function

SELECT AVG(column_name)
FROM table_name
WHERE condition;

Example

SELECT AVG(salary) as AverageSalary
from employee
where location='India';

Output