The following sections list built-in functions that you cannot overload.
Each aggregate function uses built-in functions to generate the aggregate result. You cannot overload a built-in aggregate function. Instead, you overload the necessary support functions. For a list of the aggregate functions and their related operator functions, refer to Overloading Operators for Built-In Aggregates.
You cannot overload the following functions that describe time, date, the database server, and the user.
| cardinality() | day() | month() | user |
| current | dbinfo() | sitename | weekday() |
| date() | dbservername | today | year() |
| datetime() | mdy() | trim() |
The following table lists the built-in functions for the Optical Subsystem that you cannot overload.
| descr() | volume() | family() |