ROUND returns date rounded to the unit specified by the format model fmt. This function is not sensitive to the NLS_CALENDAR session parameter. It operates according to the rules of the Gregorian calendar. The value returned is always of data type DATE, even if you specify a different datetime data type for date. If you omit fmt, then date is rounded to the nearest day. The date expression must resolve to a DATE value.
The following example rounds a date to the first day of the following year:
SELECT ROUND (TO_DATE ('27-OCT-00'),'YEAR')
"New Year" FROM DUAL;
New Year
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01-JAN-01