The optional parenthesis is syntax supported by the ODBC driver. For example:
SELECT CURRENT_DATE();
CURRENT_DATE returns the current date at the time when the request started. If CURRENT_DATE is invoked more than once during the request, the same date is returned. The date returned does not change during the duration of the request.
If you specify CURRENT_DATE without the AT clause or CURRENT_DATE AT LOCAL, then the value returned depends on the setting of the DBS Control flag TimeDateWZControl as follows:
- If the TimeDateWZControl flag is enabled, CURRENT_DATE returns a date constructed from the session time and session time zone.
- If the TimeDateWZControl flag is disabled, CURRENT_DATE returns a date constructed from the time value local to Vantage and the session time zone.
For more information, see “DBS Control (dbscontrol)” in Teradata Vantage™ - Database Utilities, B035-1102.
CURRENT_DATE returns a value that is adjusted to account for the start and end of daylight saving time (DST) only in the following cases:
- CURRENT_DATE is specified with AT [TIME ZONE] time_zone_string, where time_zone_string follows different DST and standard time zone displacements.
- CURRENT_DATE is specified with AT LOCAL or without an AT clause and the session time zone was defined with a time zone string that follows different DST and standard time zone displacements.