How to sum cells in a column if a condition is met in another column with MySQL?

For this, you can use the aggregate function SUM() along with the GROUP BY clause. Let us first create a table −

mysql> create table DemoTable    -> (    -> EmployeeName varchar(20),    -> JoiningDate date,    -> Salary int    -> ); Query OK, 0 rows affected (0.54 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable values('David','2019-11-02',400); Query OK, 1 row affected (0.52 sec) mysql> insert into DemoTable values('Robert','2018-11-25',100); Query OK, 1 row affected (0.39 sec) mysql> insert into DemoTable values('Bob','2019-12-14',600); Query OK, 1 row affected (0.25 sec) mysql> insert into DemoTable values('Carol','2019-11-03',300); Query OK, 1 row affected (0.23 sec)

Display all records from the table using select statement −

mysql> select * from DemoTable;

This will produce the following output −

+--------------+-------------+--------+ | EmployeeName | JoiningDate | Salary | +--------------+-------------+--------+ | David        | 2019-11-02  |    400 | | Robert       | 2018-11-25  |    100 | | Bob          | 2019-12-14  |    600 | | Carol        | 2019-11-03  |    300 | +--------------+-------------+--------+ 4 rows in set (0.00 sec)

Here is the query to sum cells in a column if a condition is met in another column −

mysql> select year(JoiningDate) as JoiningYear,    -> month(JoiningDate) as JoiningMonth,    -> sum(Salary) as Total,    -> group_concat(EmployeeName) as Name    -> from DemoTable    -> group by JoiningYear,JoiningMonth;

This will produce the following output −

+-------------+--------------+-------+-------------+ | JoiningYear | JoiningMonth | Total | Name        | +-------------+--------------+-------+-------------+ |        2018 |           11 |   100 | Robert      | |        2019 |           11 |   700 | David,Carol | |        2019 |           12 |   600 | Bob         | +-------------+--------------+-------+-------------+ 3 rows in set (0.04 sec)