NEXT_DAY returns the date of the first weekday named by char that is later than the date date. The return type is always DATE, regardless of the datatype of date. The argument char must be a day of the week in the date language of your session, either the full name or the abbreviation. The minimum number of letters required is the number of letters in the abbreviated version. Any characters immediately following the valid abbreviation are ignored. The return value has the same hours, minutes, and seconds component as the argument date.
This example returns the date of the next Tuesday after February 2, 2001:
SELECT NEXT_DAY('02-FEB-2001','TUESDAY') "NEXT DAY" FROM DUAL;