Initializes an instance of a Period data type.
Syntax
PERIOD ( datetime_expression [, { datetime_expression | UNTIL_CHANGED | UNTIL_CLOSED } ] )
- datetime_expression
- An expression that evaluates to a DATE, TIME, or TIMESTAMP value.
- UNTIL_CHANGED
-
A DATE or TIMESTAMP value that is considered to be forever or until it is changed.
For PERIOD(DATE) types, UNTIL_CHANGED has a value of DATE '9999-12-31'.
For PERIOD(TIMESTAMP[(n)] [WITH TIME ZONE]) types, UNTIL_CHANGED has a value of TIMESTAMP '9999-12-31 23:59:59.999999 00:00'(with the precision truncated to the precision of the beginning bound and the time zone omitted if the beginning bound does not have a time zone).
UNTIL_CHANGED supports derived periods. See IS UNTIL_CHANGED/IS NOT UNTIL_CHANGED.
- UNTIL_CLOSED
-
An ending bound for the Period value of a temporal table transaction-time column that indicates that the row is an open row.
UNTIL_CLOSED has a data type of TIMESTAMP(6) WITH TIME ZONE and a value of TIMESTAMP '9999-12-31 23:59:59.999999+00:00'.
For more information about temporal tables, see Teradata Vantage™ - Temporal Table Support , B035-1182 .
UNTIL_CLOSED supports derived periods. See IS UNTIL_CLOSED/IS NOT UNTIL_CLOSED.