MySQL AVG() Function
The MySQL AVG() function returns the average value of an expression.
Syntax
The syntax for using AVG() function is given below:
SELECT AVG(column_name) FROM table_name WHERE condition(s);
The MySQL GROUP BY clause is used to arrange result table into identical groups when one or more columns are used. Please note that it is must to include those column names in a GROUP BY clause which are not encapsulated within the AVG() function. See the syntax below:
SELECT column1, column2, ... AVG(column_name) FROM table_name WHERE condition(s) GROUP BY column1, column2, ...;
Parameters
column1, column2, ... |
Specify the column names that are not encapsulated within the AVG() function. It must be included in the GROUP BY clause. |
column_name |
Specify the column or expression whose average value need to be calculated. |
table_name |
Specify the table name from where the records need to retrieved. |
WHERE condition(s) |
Optional. Specify the condition(s). Records are selected based upon specified condition(s). |
Return Value
Returns the average value of a given expression.
Example - With Single Column
Consider a database table called Employee with the following records:
EmpID | Name | City | Age | Salary |
---|---|---|---|---|
1 | John | London | 25 | 3000 |
2 | Marry | New York | 24 | 2750 |
3 | Jo | Paris | 27 | 2800 |
4 | Kim | Amsterdam | 30 | 3100 |
5 | Ramesh | New Delhi | 28 | 3000 |
6 | Huang | Beijing | 28 | 2800 |
To get the average salary of employee with age greater than 25, the following query can be used:
SELECT AVG(Salary) AS AvgSalary FROM Employee WHERE Age > 25;
This will produce the result as shown below:
AvgSalary |
---|
2925.0 |
Example - Using DISTINCT
The DISTICT clause can be used with AVG() function. For example - To get the average value of distinct (unique) salaries, the following code can be used:
SELECT AVG(DISTINCT Salary) AS AvgUniqueSalary FROM Employee;
This will produce the result as shown below:
AvgUniqueSalary |
---|
2912.5 |
Example - Using Formula
The expression contained within the AVG() function does not need to be a single field. A formula can also be used with this function. For example - Consider a bonus (15% of Salary) is given to each employee, and to calculate the average of bonus amount, the following query can be used:
SELECT AVG(Salary * 0.15) AS AvgBonusAmount FROM Employee;
This will produce the result as shown below:
AvgBonusAmount |
---|
436.25 |
Example - Using GROUP BY
To get the average salary of employees group by their age, the following query can be used:
SELECT Age, AVG(Salary) AS AvgSalaryByAge FROM Employee GROUP BY Age;
This result of the above code will be:
Age | AvgSalaryByAge |
---|---|
24 | 2750.0 |
25 | 3000.0 |
27 | 2800.0 |
28 | 2900.0 |
30 | 3100.0 |
❮ MySQL Functions