Using lambda functions

Instead of using a generator, you can write queries using the lambda function:

Customer.select(lambda c: sum(c.orders.price) > 1000)

From the point of the translation the query into SQL there is no difference, if you use a generator or a lambda. The only difference is that using the lambda you can only return entity instances - there is no way to return a list of specific entity attributes or a list of tuples.