> sum(quantity)*sum(price)/sum(quantity)

I'd say you need sum(quantity*price)/sum(quantity) for the average price, or simply avg(price).
sum(quantity)*sum(price)/sum(quantity) is definately equal to sum(price), which is not the avarage price.

For your main question: You need a third select if the second one has no result, I don't see a way to put it inside a single SQL select.

The question is, do you want to take nearest date after m.ldend or nearest before m.ldfirst
or nearest to any of those two dates?

Bye, Olaf.