Although not recommended, you can specify a numeric type in the assignment of a DATE type. Teradata Database performs implicit numeric-to-DATE type conversion prior to the assignment. The value of the numeric type must represent a valid date.
However, for comparison operations involving a numeric type operand and a DATE type operand, Teradata Database converts the DATE type to a numeric type. If you compare a numeric type and a DATE type and expect the comparison to be between two DATE types, you must explicitly convert the numeric type to a DATE type.