SELECT x.*
, x.cf1+x.cf2 sub_total
, SUM(y.cf1+y.cf2) running
FROM 1_bugs x
JOIN 1_bugs y
ON y.id <= x.id
GROUP
BY x.id;
+----+------------+-----+-----+-----------+---------+
| id | date | cf1 | cf2 | sub_total | running |
+----+------------+-----+-----+-----------+---------+
| 1 | 2016-07-19 | 3 | 2 | 5 | 5 |
| 2 | 2016-07-19 | 2 | 1 | 3 | 8 |
| 3 | 2016-07-22 | 2 | 2 | 4 | 12 |
+----+------------+-----+-----+-----------+---------+
