How to Use the AVG function in MySQL to calculate the average value,
The AVG function of MySQL is used to obtain the average value of fields in various records.
For more information about the AVG function, consider that the EMPLOYEE_TBL table has the following records:
mysql> SELECT * FROM employee_tbl;+------+------+------------+--------------------+| id | name | work_date | daily_typing_pages |+------+------+------------+--------------------+| 1 | John | 2007-01-24 | 250 || 2 | Ram | 2007-05-27 | 220 || 3 | Jack | 2007-05-06 | 170 || 3 | Jack | 2007-04-06 | 100 || 4 | Jill | 2007-04-06 | 220 || 5 | Zara | 2007-06-06 | 300 || 5 | Zara | 2007-02-06 | 350 |+------+------+------------+--------------------+7 rows in set (0.00 sec)
Now, if you want to calculate the average value of all dialy_typing_pages based on the preceding table, you can run the following command:
mysql> SELECT AVG(daily_typing_pages) -> FROM employee_tbl;+-------------------------+| AVG(daily_typing_pages) |+-------------------------+| 230.0000 |+-------------------------+1 row in set (0.03 sec)
You can set the average number of records using the group by clause. The following example takes an average of all relevant records of a person, and the average page printing paper of each person.
mysql> SELECT name, AVG(daily_typing_pages) -> FROM employee_tbl GROUP BY name;+------+-------------------------+| name | AVG(daily_typing_pages) |+------+-------------------------+| Jack | 135.0000 || Jill | 220.0000 || John | 250.0000 || Ram | 220.0000 || Zara | 325.0000 |+------+-------------------------+5 rows in set (0.20 sec)