Advanced

Grouping By

Grouping by

Last Before

Using Kleisli and Lifted

If you wrap these you get a few benefits:

• The resulting columns have more readable names
• You can use the resulting functions as methods
• They add on the group bys of their source.

How it Works

Basically the internal representation of a query is as a graph. Query combinators are just transformations on this graph. Before generating the SQL, LambdaQuery performs a reduction algorithm on this graph, and then the reduced graph is compiled to SQL. To see the SQL of the unreduced graph, use the reduce=False option for the Query.sql method.