Group data by Custom Period Ranges Using a Reference Date If for example, I have a table that looks like this:

+----+--------+---------------------+
| id | volume |      createdAt      |
+----+--------+---------------------+
|  1 |   0.11 | 2018-01-26 13:56:01 |
|  2 |   0.34 | 2018-01-28 14:22:12 |
|  3 |   0.22 | 2018-03-11 11:01:12 |
|  4 |   0.19 | 2018-04-13 12:12:12 |
|  5 |   0.12 | 2014-04-21 19:12:11 |
+----+--------+---------------------+


I want to perform a query that can accept  starting point and then loop through a given number of days, and then group by that date range. 

For instance, I'd like the result to look like this:

+------------+------------+--------+
| enddate    | startdate  | volume |
+------------+------------+--------+
| 2018-04-25 | 2018-04-12 |   0.31 |
| 2018-04-11 | 2018-03-29 |   0.00 |
| 2018-03-28 | 2018-03-15 |   0.00 |
| 2018-03-14 | 2018-03-01 |   0.22 |
| 2018-02-28 | 2018-02-15 |   0.00 |
| 2018-02-14 | 2018-02-01 |   0.00 |
| 2018-01-31 | 2018-01-18 |   0.45 |
| ...        | ...        |    ... |
+------------+------------+--------+


In essence, I want to be able to input a start_date e.g 2018-04-25, a time_interval e.g. 14, like in the illustration above and then the query will sum the volumes in that time range. 

I know how to use INTERVAL with the DATE_SUB() and the DATE_ADD() functions but I cannot figure out how to perform the loop I think is necessary.

Please help.
I hope I understand this right and you can use this for at least a start.

SELECT x.startdate + INTERVAL (x.days + 1) DAY enddate,
       x.startdate,
       (SELECT sum(t.volumes)
               FROM tab t
               WHERE t.createdAt &gt;= x.startdate
                     AND t.createdAt &lt; x.startdate + INTERVAL (x.days + 1) DAY) volume
       FROM (SELECT '2018-04-12' startdate,
                    12 days
             UNION
             SELECT '2018-03-29' startdate,
                    12 days
             UNION
             SELECT '2018-03-15' startdate,
                    12 days
             UNION
             SELECT '2018-03-01' startdate,
                    12 days
             UNION
             SELECT '2018-02-15' startdate,
                    12 days
             UNION
             SELECT '2018-02-01' startdate,
                    12 days
             UNION
             SELECT '2018-01-18' startdate,
                    12 days) x;


I haven't quite gotten on how you'd like to specify the dates and intervals though. Maybe you can clarify that, than I can probably edit this in.