SELECT CreatedDate, Account.CreatedDate FROM Opportunity
WHERE CALENDAR_YEAR(CreatedDate) = 2016

SELECT CreatedDate, Account.CreatedDate FROM Opportunity
WHERE CALENDAR_YEAR(Account.CreatedDate) = 2016

SELECT CreatedDate, Account.CreatedDate FROM Opportunity
WHERE CALENDAR_YEAR(CreatedDate) = CALENDAR_YEAR(Account.CreatedDate)

SELECT CreatedDate, Account.CreatedDate FROM Opportunity
WHERE CALENDAR_YEAR(CreatedDate) = : CALENDAR_YEAR(Account.CreatedDate)