I don't totally understand but would this do it?
db(db.memo_store.created_by==auth.user.id)(db.viewed_memos.memo==db.memo_store.id).select()
I don't totally understand but would this do it?
db(db.memo_store.created_by==auth.user.id)(db.viewed_memos.memo==db.memo_store.id).select()