Oracle LAST_DAY() Function

Oracle LAST_DAY() is a built-in function that returns the last day of the month for a given date.

Oracle `LAST_DAY()` Syntax

Here is the syntax for the Oracle LAST_DAY() function:

LAST_DAY(date)

The Oracle LAST_DAY() function returns the last day of the month for a given date.

The return type of the LAST_DAY() function is always DATE, regardless of the data type of the input date parameter.

If either argument is NULL, LAST_DAY() returns NULL.

Here are some examples that demonstrate the usage of the Oracle LAST_DAY() function.

ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD';
SELECT
    LAST_DAY(DATE '2023-02-11')
FROM dual;

Output:

LAST_DAY(DATE'2023-02-11')
_____________________________
2023-02-28

Here, we use the ALTER SESSION statement to modify the date display format of the current session.

To get the last day of the current month, use the SYSDATE or CURRENT_DATE function:

ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD';
SELECT
    LAST_DAY(SYSDATE),
    LAST_DAY(CURRENT_DATE)
FROM dual;

Output:

LAST_DAY(SYSDATE)    LAST_DAY(CURRENT_DATE)
____________________ _________________________
2023-02-28           2023-02-28

If either argument is NULL, LAST_DAY() returns NULL.

SET NULL 'NULL';
SELECT
    LAST_DAY(NULL)
FROM dual;

Output:

LAST_DAY(NULL)
_________________
NULL

Here, we use the SET NULL 'NULL'; statement to display NULL values as the string 'NULL'.

Oracle LAST_DAY() is a built-in function that returns the last day of the month for a given date.