Hi UAL747-600 (???),
Your question is very hard to answer due to many reasons. First of all you have to find two airlines which operate those types on the same routes. Second if you find them it is hard to compare the figures of operational costs, as many factors must be considered to receive "operational costs". Just imagine, does the airline just operate one type of aircraft? Or do they use A319/320/321 as a family? Is it a low-cost-carrier or a full-service carrier? How much do the pilkots and cabin crew earn? Many many more factors affect the costs of operating one aircraft type.
It is simple: Boeing says their aircraft is cheaper to operate. Airbus says the same about their own aircraft. The truth is: No aircraft is cheaper than the other one in general: It depends on the airline and its structure to decide which aircraft is the best for it.
And please don't start an Airbus-Boeing fight again, I'm so sick with it and will turn crazy if I see it again...
Just love aviation, don't fight like little boys!
Me & You & a Plane Named Blue...