In MariaDB, DAYOFMONTH() is a built-in date and time function that returns the day of the month from a given date.
It accepts one argument, which is the date you want to extract the day of the month from.
The result is in the range 1 to 31. However, if the date has a zero day part (for example '0000-00-00' or '2021-00-00'), the result is 0.