Example

Teradata Vantageā„¢ Data Types and Literals

brand
Software
Teradata Vantage
prodname
Teradata Database
Teradata Vantage NewSQL Engine
vrm_release
16.20
category
Programming Reference
featnum
B035-1143-162K

Assume that the current date is DATE '2008-05-14' at time zone displacement, INTERVAL '09:00' HOUR TO MINUTE, but the current date is DATE '2008-05-13' at time zone displacement, INTERVAL '04:00' HOUR TO MINUTE. The following SELECT statement returns the result: TIMESTAMP '2008-05-13 08:30:00+04:00'.

SET TIME ZONE INTERVAL '09:00' HOUR TO MINUTE;
SELECT CAST(TIME '08:30:00+04:00' AS TIMESTAMP(0) WITH TIME ZONE 
   AT SOURCE);

The time zone displacement, INTERVAL '04:00' HOUR TO MINUTE, in the literal is used to determine the UTC value '04:30:00' and time zone displacement, INTERVAL '04:00' HOUR TO MINUTE, of the literal. For the CAST, the source expression value '04:30:00' at UTC is adjusted to the time zone displacement of the source expression, INTERVAL '04:00' HOUR TO MINUTE, to yield '08:30:00'.

A timestamp is formed from the current date '2008-05-13' at time zone displacement, INTERVAL '04:00' HOUR TO MINUTE, and the time portion of the source expression value '08:30:00' obtained after the above adjustment. Then this timestamp '2008-05-13 08:30:00' at time zone displacement, INTERVAL '04:00' HOUR TO MINUTE, is adjusted to UTC so that the CAST result is '2008-05-13 04:30:00' at UTC with time zone displacement, INTERVAL '04:00' HOUR TO MINUTE.

The result value of the CAST at UTC is adjusted to time zone, INTERVAL '04:00' HOUR TO MINUTE, so the result of the SELECT statement is: TIMESTAMP '2008-05-13 08:30:00+04:00'. The current session time zone has no effect.