The FROM_DAYS() function returns a date by specifying "Number of days".
The value is based on the number of days from the start of the default calendar 0000-00-00.
The function is not intended for use with dates prior to the introduction of the Gregorian calendar in 1582.
The results are not reliable because the function does not take into account lost days due to the Julian calendar change.
The minimum value to get a result is 366. Smaller values or invalid values will return an empty result.
If the value of "Number of days" is NULL, the FROM_DAYS() function returns NULL.
If the value of "Number of days" is 0, the function returns NULL on MariaDB, and an empty result on MySQL 8.0.
The FROM_DAYS() function is the inverse of the TO_DAYS() function.