In this example, the TruncRoundReturnTimestamp DBS Control field is set to TRUE; therefore, TRUNC returns a TIMESTAMP value when the input data type is TIMESTAMP.
SELECT TRUNC(cast('2000-08-04 22:00:00-05:00' as timestamp with time zone), 'DD');
Result:
TRUNC('2000-08-04 22:00:00-05:00','DD') --------------------------------------- 2000-08-04 00:00:00.000000-05:00