SELECT Statements and Derived Period Columns
A SELECT * on a table with a derived period column returns the two DATE or TIMESTAMP columns used to define the derived period column, not the derived period column. The two DATE or TIMESTAMP columns appear as regular columns in a nontemporal table.
You can only specify derived period columns with period predicate operators, begin and end bound functions, duration functions, comparison operators, logical predicate operators, and in the EXPAND clause. For example, you cannot specify derived period columns in WITH or HAVING clauses. You cannot specify derived period columns in functions, macros, or stored procedures such as P_INTERSECT, P_NORMALIZE, LDIFF, or RDIFF, except in a WHERE clause.
You cannot specify derived period columns in the select list.