Power Query - Merge column based on from date?

I need help! I'm trying to find a way to match the hours billed to the amount charged. If one table has columns (date, hours), and another table has (hourly rate, from date), how would I get a table that list (date, hours, hourly rate). Right now I write a conditional column, but I don't want to have to manually edit the query every time the rate changes. Thanks