Insert all dates from a month into a table I'm confused. How to get all dates from a month and insert them into a table in a database?

I want to do this with a trigger so when I make a period, ex April 01-04-2016 / 30-04-2016, then in table attendance it will generate one row for each date.

I have table period

period | start_period | end_period
April  |   2016-04-01 | 2016-04-30


and I have table attendance

attendance_date  | check_in | check out
2016-04-01       |     null |      null
..........
2016-04-30       |     null |      null


How to get all dates between 01-04-2016 and 30-04-2016 and insert them into table attendance?
You can use variables to mimic a recursive CTE:

SELECT @d:=(@d + interval 1 day) 
FROM (SELECT @d:=date('2016-03-31')) r
CROSS JOIN information_schema.tables t 
WHERE @d &lt; '2016-04-30';


You need to make sure that you have a table to join against that have a sufficient number of rows for your need.

If you do this on a regular basis you might want to generate a calendar table that you can use to join against.

I heard rumors that recursive CTE:s as well as window functions will be available in a nearby future for MySQL. I have not investigated it very closely though, so it might just be rumours.