I have two columns (buying prince and sale price) and I want to calculate the difference between them. After that I want to order the result so I can see all the profit marg
SELECT (sale_price - buy_price) AS profit
FROM table_name
ORDER BY profit DESC
Joe has it, but I think you might be looking for something slightly different for the ordering.
Profit margin is defined as net income / revenue.. so the profit margin of each product would be (sale_price minus buy price) divided by sale_price.
SELECT (sale_price - buy_price) AS profit FROM table_name
ORDER BY ((sale_price - buy_price) / sale_price) DESC
Good luck.