Here is a query to quickly display "Posting Periods":-
Select * from (SELECT T0.[FinncPriod] as [Posting Period], datepart(month,T0.[DocDate]) AS Month, datepart(year,T0.[DocDate]) AS Year FROM OINV T0) as x GROUP BY [Posting Period], Month, Year ORDER BY [Posting Period] DESC
Kindest regards,
Alan