Join on all dates within the range MySQL - php

Question

I have the following table :
administratieID | varchar
getalTypeNaam | varchar
datum | date
waarde | double
With the following query:
Select administratieID AS AI, waarde WA, datum DT
from getalType
where getalTypeNaam = 'test'
and datum between DATE_SUB(NOW(), INTERVAL 10 DAY) and DATE_SUB(NOW(), INTERVAL 15 DAY)
order by datum
What I want is that I can do a select where all the dates between the specified dates are returned even if there is nothing in the database that coresponds with that date. I want this even if there is no value but in that case i want to return the value 0.
So I want this in return:
date administratieID waarde
10-10-2016 xxx 10
11-10-2016 xxx 0 <-- no data available
12-10-2016 xxx 40
13-10-2016 xxx 9
14-10-2016 xxx 0 <-- no data available
Now I get this:
date administratieID waarde
10-10-2016 xxx 10
12-10-2016 xxx 40
13-10-2016 xxx 9

Answer 1

There are ways to do this, but they are quite hackish...
One would be to have an inline incrementing variable, and use a dummy table that you know has at least as many records in it as the maximum number of days in your date range. Then you can do something like this:
SET #date = DATE_SUB(NOW(), INTERVAL 15 DAY); #or whatever the earliest date you need is
SELECT DISTINCT
IFNULL(administratieID,'XXX') AS AI
, IFNULL(waarde,0) AS WA
, all_dates AS DT
FROM
(SELECT #date:=DATE_ADD(#date, INTERVAL 1 DAY) AS all_dates
FROM
my_dummy_table_with_lots_of_records
WHERE #date >= DATE_SUB(NOW(), INTERVAL 15 DAY) AND #date <= DATE_SUB(NOW(), INTERVAL 10 DAY)) d LEFT JOIN
getalType t ON
DATE_FORMAT(all_dates,'%Y-%m-%d') = DATE_FORMAT(t.datum,'%Y-%m-%d')
WHERE
IFNULL(getalTypeNaam, 'Test') = 'Test' #if there's no data we still need to return something
ORDER BY all_dates;
Another easier way is just to have a table called "all_dates", which you can use in the join. The table would just have one column, "datum" and you populate it with every possible date that could be used in the getalType table. This could even be done with a trigger.
Then you link to this table, instead of doing all the derived nonsense above.
This would also avoid having to have multiple sql statements, as you don't have a variable that needs initialising.