this is for getting the maximum ( for CId ) and minimum for order (firstOrder)
if for all post order is less then firstOrder then we change the firstOrder with the post order.
the issue was that if the blog is empty we had CId == 0 and we delete de CId and order from request
but if all posts where deleted from blog then there is CId and that is ok but no order and request where made with fist.order = Infinity wich wasn't good.
So here we check if the firstOrder wasn't  updated then delete order from request.