Filling in the date gaps mysql query for ajax call [duplicate] - php

Question

This question already has answers here:
What is the most straightforward way to pad empty dates in sql results (on either mysql or perl end)?
(9 answers)
Closed 5 years ago.
What is the best way to include empty dates for a time series graph generated from a mysql db.
If I run a query to get say all of the red cars sold on a particular day I could run :
SELECT count(car_sale_order) as 'count', DATE(sale_date) as 'sale_date'
FROM car_sales
WHERE colour = "red";
but the results could have date holes in them i.e.
------------------
count | sale_date
------------------
2 | 2017-09-03
10 | 2017-09-04
1 | 2017-09-07
23 | 2017-09-09
45 | 2017-09-10
2 | 2017-09-11
21 | 2017-09-12
when what id really like is :
------------------
count | sale_date
------------------
2 | 2017-09-03
10 | 2017-09-04
0 | 2017-09-05
0 | 2017-09-06
1 | 2017-09-07
0 | 2017-09-08
23 | 2017-09-09
45 | 2017-09-10
2 | 2017-09-11
21 | 2017-09-12
I use PHP so know that i could generate this stuff at that side but it would be really handy to just have the result set include this from the get go....
This isn't the same as What is the most straightforward way to pad empty dates in sql results (on either mysql or perl end)?
I'm looking for a MySQL only result

Answer 1

Consider using a calendar table. I have always found this to be the most reliable way to create date reports as you have a row for every date which you join with your table. In your case, you may wish to use something like:
SELECT count(car_sale_order) as 'count', DATE(sale_date) as 'sale_date'
FROM calendar_table
LEFT JOIN car_sales ON calendar_table.date = car_sales.sale_date
WHERE calendar_table.date BETWEEN '2017-01-01' and '2017-01-31' and colour = "red";