DATE MAKEDATE(INT year, INT dayofyear)
Returns a date, given year and day-of-year values. dayofyear must be greater than 0 or the result is NULL.
mysql> select makedate(2021,1), makedate(2021,100), makedate(2021,400); +-------------------+---------------------+---------------------+ | makedate(2021, 1) | makedate(2021, 100) | makedate(2021, 400) | +-------------------+---------------------+---------------------+ | 2021-01-01 | 2021-04-10 | 2022-02-04 | +-------------------+---------------------+---------------------+
MAKEDATE