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
.
Syntax
The syntax goes like this:
DAYOFMONTH(date)
Where date
is the date to extract the day from.
Example
Here’s an example:
SELECT DAYOFMONTH('2030-01-25');
Result:
+--------------------------+ | DAYOFMONTH('2030-01-25') | +--------------------------+ | 25 | +--------------------------+
Datetime Values
It also works with datetime values:
SELECT DAYOFMONTH('2030-01-25 10:30:45');
Result:
+-----------------------------------+ | DAYOFMONTH('2030-01-25 10:30:45') | +-----------------------------------+ | 25 | +-----------------------------------+
Zero Days
Here’s an example that uses a zero day in the date:
SELECT DAYOFMONTH('2030-00-00');
Result:
+--------------------------+ | DAYOFMONTH('2030-00-00') | +--------------------------+ | 0 | +--------------------------+
Numeric Dates
It’s also possible to pass dates as a number, as long as it makes sense as a date.
Example
SELECT DAYOFMONTH(20300125);
Result:
+----------------------+ | DAYOFMONTH(20300125) | +----------------------+ | 25 | +----------------------+
Or even the following (which uses a two-digit year):
SELECT DAYOFMONTH(300125);
Result:
+--------------------+ | DAYOFMONTH(300125) | +--------------------+ | 25 | +--------------------+
But it must make sense as a date. Here’s what happens if I increase the day part to an invalid day:
SELECT DAYOFMONTH(20300135);
Result:
+----------------------+ | DAYOFMONTH(20300135) | +----------------------+ | NULL | +----------------------+
Other Delimiters
You can use other delimiters for the date. MariaDB is quite forgiving when it comes to delimiters on dates. Here are some valid examples:
SELECT
DAYOFMONTH('2030/01/25'),
DAYOFMONTH('2030,01,25'),
DAYOFMONTH('2030:01:25'),
DAYOFMONTH('2030;01!25');
Result (using vertical output):
DAYOFMONTH('2030/01/25'): 25 DAYOFMONTH('2030,01,25'): 25 DAYOFMONTH('2030:01:25'): 25 DAYOFMONTH('2030;01!25'): 25
Current Date
We can pass NOW()
as the date argument to use the current date:
SELECT
NOW(),
DAYOFMONTH(NOW());
Result:
+---------------------+-------------------+ | NOW() | DAYOFMONTH(NOW()) | +---------------------+-------------------+ | 2021-05-13 09:02:41 | 13 | +---------------------+-------------------+
Invalid Arguments
When passed an invalid argument, DAYOFMONTH()
returns null
:
SELECT DAYOFMONTH('Homer');
Result:
+---------------------+ | DAYOFMONTH('Homer') | +---------------------+ | NULL | +---------------------+
Missing Argument
Calling DAYOFMONTH()
with the wrong number of arguments, or without passing any arguments, results in an error:
SELECT DAYOFMONTH();
Result:
ERROR 1582 (42000): Incorrect parameter count in the call to native function 'DAYOFMONTH'
And another example:
SELECT DAYOFMONTH('2030-01-25', '2045-05-08');
Result:
ERROR 1582 (42000): Incorrect parameter count in the call to native function 'DAYOFMONTH'