TIMESTAMP_ISO

Returns a timestamp value based on date, time or timestamp arguemnt. If the argument is a date, it inserts zero for all the time elements. If the argument is a time, it inserts the value of CURRENT DATE for the date elements and zero for the fractional time element. The argument must be a date, timestamp, or a valid character string representation of a date or timestamp that is neither CLOB nor a LONG VARCHAR.

The result of the function is TIMESTAMP. The result will be null if the argument is null.