FULL_YEARS

Calculates the number of full years between the two dates as an integer constant. Full year difference between 31/12/2004 and 01/01/2005 is 0

FULL_YEARS (start, end)

Two attributes of the Date type or date constants or calculations producing date

Number: the count of full years between the two dates.

IF FULL_YEARS (Account.OpeningDate, Account.ClosingDate) = 5 THEN ...