Compute sum for summer months

Question

Table schema:

Reader_id
Date
Minutes_read
Book_id

I want to extract the month from a date ‘2021-07-15’ to sum the total time spent reading books in summer months (06-08) for each reader.

So my final table would something like

Reader_id | summer_reading_time

Answer 1

If your data spans multiple years, you cannot simply extract a time range. Consider EXTRACT():

SELECT Reader_id, sum(Minutes_read) AS summer_reading_time
FROM   tbl
WHERE  EXTRACT(month FROM date) BETWEEN 6 AND 8
GROUP  BY 1;