MySQL. 3 tables, How to subtract table A - table B then update to table C? : <p>I have 3 tables (inprod, outprod, Products), I want to update it every time a new row comes in. What I want to know is, how can I update it in a single query using Join? The columns affected are ProdName and stocksIn, exists in these 3 tables. Simply put, products = inprod - outprod.</p>
