I have written some code to update certain rows of a table with a decreasing sequence of numbers. To select the correct rows I have to JOIN two tables. The last row in the table needs to have a value of 0, the second last -1 and so on. To achieve this I use ORDER BY DESC. Unfortunately my code brings up the following error: Incorrect usage of UPDATE and ORDER BY My reading suggests that I can't use UPDATE, JOIN and ORDER BY together. I've read that maybe subqueries might help? I don't really have any idea how to change my code to do this. Perhaps someone could post a modified version that will work? while($row = mysql_fetch_array( $result )) { $products_id = $row['products_id']; $products_stock_attributes = $row['products_stock_attributes']; mysql_query("SET @i = 0"); $result2 = mysql_query("UPDATE orders_products op, orders ord SET op.stock_when_purchased = (@i:=(@i - op.products_quantity)) WHERE op.orders_id = ord.orders_id AND op.products_id = '$products_id' AND op.products_stock_attributes = '$products_stock_attributes' AND op.stock_when_purchased < 0 AND ord.orders_status = 2 ORDER BY orders_products_id DESC") or die(mysql_error()); }