Hey,
So I have three tables, Sales, Purchases & Inventory. I have 3 items A, B, C. In each sale, a customer can buy all three, just two or one of the items in whatever quantity they wish. On each day I make purchases of varying quantities of A, B & C. I cannot figure out how to use rollup to give me a total of purchases, sales and purchases - sales in my inventory. Images of my three tables below.