MySQL select accumulated (running sum) column?

To select accumulated column, let us first create a demo table. The query to create a table is as follows −

mysql> create table accumulatedDemo
   -> (
   -> Value int
   -> );
Query OK, 0 rows affected (0.58 sec)

Insert some records in the table using insert command. The query is as follows −

mysql> insert into accumulatedDemo values(10);
Query OK, 1 row affected (0.21 sec)
mysql> insert into accumulatedDemo values(15);
Query OK, 1 row affected (0.09 sec)
mysql> insert into accumulatedDemo values(20);
Query OK, 1 row affected (0.13 sec)
mysql> insert into accumulatedDemo values(25);
Query OK, 1 row affected (0.12 sec)
mysql> insert into accumulatedDemo values(45);
Query OK, 1 row affected (0.14 sec)

Display all records from the table using select statement. The query is as follows −

mysql> select *from accumulatedDemo;

Here is the output −

+-------+
| Value |
+-------+
| 10    |
| 15    |
| 20    |
| 25    |
| 45    |
+-------+
5 rows in set (0.00 sec)

The following is the query to select accumulated column −

mysql> set @previousSum =0;
Query OK, 0 rows affected (0.00 sec)
mysql> select Value, @previousSum: =@previousSum+ Value AS AccumulatedColumn from accumulatedDemo;

Here is the output −

+-------+-------------------+
| Value | AccumulatedColumn |
+-------+-------------------+
| 10    | 10                |
| 15    | 25                |
| 20    | 45                |
| 25    | 70                |
| 45    | 115               |
+-------+-------------------+
5 rows in set (0.00 sec)