In the following table, x represents a datetime or a timestamp.
| Function | Description |
| ADD_MONTHS(x, y) | Add y months to x. If y is negative, y months are subtracted from x. |
| LAST_DAY(x) | Get the last day of the month. |
| MONTHS_BETWEEN(x, y) | Returns the number of months between x and y. If x appears before y on the calendar, the number returned is positive. |
| NEXT_DAY(x, day) | Returns the datetime of the next day following x; day is specified as a literal string, for example SATURDAY. |
| NEW_TIME | Returns the time/day value from a time zone specified by the user. |
| ROUND(x [, unit]) | Rounds x. By default, x is rounded to the beginning of the nearest day. You may supply an optional unit string to indicate the rounding unit. |
| SYSDATE() | Returns the current datetime set for the operating system. |
| TRUNC(x [, unit]) | Truncates x. By default, x is truncated to the beginning of the day. You may supply an optional unit string that indicates the truncating unit. |