Need help with learning expressions

Im trying to learn how to use expressions. I took a look at the guide over at, however my english is not good enough that I can understand the function of every thing.

Im trying to make a query using the IN RANGE construct that shows DPS only when the person is at full health. I came up with the following but it returns no data:

NOT IN RANGE FROM resources.hitPoints < resources.maxHitPoints TO resources.hitPoints = resources.maxHitPoints GROUP BY source END


Can someone help me decodify how IN RANGE works? And how I would go about making such a query? Thanks!