Ranges query gone wild

Hi. I have a MySQL table where a product price ranges are set according to quantities. For instance for a certain product you'd have (besides id columns): range_begin | range_end | range_price 0 | 35 | 1.5 36 | 70 | 2 71 | - | 3 Where '-' is always the character that means '..and above' and closes the entire range field. So in the above example a quantity of 71 and above has a price tag - $3. I have limited success with writing the simple query that when given a quantity returns its correct price range. This is what I came up with: SELECT range_price FROM price_ranges WHERE product_id = '$product_id' && size_id = '$size_id' && ((range_begin <= '$quantity' && range_end = '-') || (range_begin <= '$quantity' && range_end >= '$quantity')); It partially works. But given the above example, it'll correctly return for a quantity of 71-79 the price of 3, but for anything above that it'll return the wrong price - 1.5. It works fine if I remove the second part of the OR construct. Also it returns nothing for the quantities of 4-9 (?!). I've tested this on my machine (MySQL ver: 3.23.54) and on the customer's server (ver: 4.0.14), and got the same results. Obviously I'm not getting the logical scheme right. If anyone can point out the problem or suggest a better way to write the query I'd appreciate it. Thank you, Boaz Amit