Stock Control Queries & Reports from MySQL database

I have developed a MySQL database for a take away shop that stores: 1. all the products 2. all the sales data 3. all the purchases 4. all the inventory I now want to have a query and report written that calculates on a daily basis what the stock should be and the compares that with the actual stock which is entered manually. The creation of records for daily sales should be done via a script once the total daily sales data has been entered. The creation of records for daily inventory data should also be automated