I want to be able to sort by two columns, but only if a 3rd column has a value in that row.

I.e. Column A is the price, Column B is the date, and Column C is the quantity.

I need to sort by Price, then Date, but ONLY if there is a value on that row in the Quantity column. Any rows with no value or where value = 0 in the Quantity column can sort below those with values and be ignored. Essentially, I want to see prices and dates for anything that has a current quantity (in stock).

Thanks for any help.