I need to get SUMs from two different related tables, and I'm stumped as to how (and haven't managed to successfully slog through the documentation). SELECT si_invoices.index_id, si_invoices.date, ...

edit: I didn't read the whole question. :facepalm: But basically, grouping by the day of week in place of date should get you where you want to go. Start with the query you posted above, then use that ...