Timeseries chart with aggregation over overlapping intervals - google-data-studio

Question

My dataset is of the following form:
Start Date End Date Count Contact
2019-01-20 2019-05-10 50 A
2019-03-05 2019-06-07 20 A
2019-03-05 2019-06-07 20 B
....
I want a timeseries chart where the X axis is months, and the Y axis is the total count.
E.g.
The entries would be
Month TotalCount Contact
Jan 50 A
Jan 0 B
Feb 50 A
Feb 0 B
Mar 70 A
Mar 20 B
Apr 70 A
Apr 20 B
May 70 A
May 20 B
Jun 20 A
Jun 20 B
Jul 0 A
Jul 0 B
...
How can I achieve this in Data Studio? The data is coming from bigquery.

Answer 1

You wouldn't be able to do that in Data Studio visually alone without manipulating your dataset first.
You could instead use a custom query to generate the a date range of month starts (https://cloud.google.com/bigquery/docs/reference/standard-sql/functions-and-operators#generate_date_array) and then join all rows from your dataset where the month start or between your start date and end date.
Example code for your example
WITH CTE AS (
SELECT date('2019-01-20') start_date, date('2019-05-10') end_date, 50 count, 'A' contact
UNION ALL SELECT date('2019-03-05'), date('2019-06-07'), 20, 'A'
UNION ALL SELECT date('2019-03-05'), date('2019-06-07'), 20, 'B'
), monthDates AS (
SELECT months FROM
UNNEST(GENERATE_DATE_ARRAY('2019-01-01', '2019-07-01', INTERVAL 1 MONTH)) months
), monthContact AS (
SELECT months, contact
FROM monthDates m
CROSS JOIN CTE
GROUP BY 1,2
)
SELECT months, ifnull(sum(count),0) count, m.contact
FROM monthContact m
LEFT JOIN CTE c ON m.months BETWEEN start_date AND end_date AND m.contact = c.contact
GROUP BY 1,3
ORDER BY 1,3