Show all dates between, even if no result In group by - mysql

Question

SELECT Count(Phq_2) as Phq_2, Date(created) as created
FROM `survey`
WHERE Phq_2 != ''
GROUP BY Date(created)
ORDER BY Date(created) ASC
Showing this
Expected Result

Answer 1

you can create a list of dates where you can use to list and join on your table. table c on the query below is the date table.
SELECT c.date,
COUNT(s.phq_2)
FROM (select adddate('1970-01-01',t4.i*10000 + t3.i*1000 + t2.i*100 + t1.i*10 + t0.i) date from
(select 0 i union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t0,
(select 0 i union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t1,
(select 0 i union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t2,
(select 0 i union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t3,
(select 0 i union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t4
) c
LEFT JOIN `survey` s
ON c.date = s.created
WHERE s.phq_2 != ''
AND c.date BETWEEN '2017-08-30' AND '2017-09-06'
GROUP BY c.date
ORDER BY c.date
Result
date COUNT(s.phq_2)
2017-08-30 1
2017-08-31 1
2017-09-01 0
2017-09-02 0
2017-09-03 0
2017-09-04 0
2017-09-05 1
2017-09-06 6
if you want the dates fixed for WHERE c.date BETWEEN '2017-08-30' AND '2017-09-06', you can use the resulting MIN() and MAX() of column created from your table in a sub-query