Is it possible to aggregate (ex. sum) over related fields without SQL

I am building a query using a multi-multi relationship table (connecting orders with line items). I am able to filter from related tables without a problem (example: and, but I only get simple views (Count of rows, Distinct values). I wanted to do a sum over a column in related table (ie: line_item.quantity) and was unable to do so.

I had to write custom SQL which does:

SELECT sum("woocommerce_line_item__via__wo"."quantity") AS "sum",...

to achieve this. Is it possible the same thing without custom SQL?