PapaBurgundy Posted May 17, 2011 Share Posted May 17, 2011 Hi, I have a mysql_query within PHP that multiplies the price of a product by the quantity bought of that product to give a subtotal. products.product_price * order_prod.order_quan AS product_subtotal This works fine and is called upon using ($get_data['product_subtotal'] As you would expect. My only problem is that I need to get a total order cost. I thought that it would merely be a case of doing something like SUM(product_subtotal) AS total_order_price But this brings back nothing. I know this must be very simple as it's only adding together a few values, but I've been stuck on this same problem for hours and time is running out ahhh Any ideas? Link to comment https://forums.phpfreaks.com/topic/236634-finding-the-sum-of-a-sum/ Share on other sites More sharing options...
mikosiko Posted May 17, 2011 Share Posted May 17, 2011 post more code Link to comment https://forums.phpfreaks.com/topic/236634-finding-the-sum-of-a-sum/#findComment-1216481 Share on other sites More sharing options...
PapaBurgundy Posted May 17, 2011 Author Share Posted May 17, 2011 $sql = "SELECT products.product_id, products.product_price, order_prod.order_quan, products.product_price * order_prod.order_quan AS product_subtotal"." FROM products, order_prod"." WHERE products.product_id = order_prod.product_id "." AND order_prod.order_id = " . $_GET["order_id"]." ORDER BY products.product_id"; $get = mysql_query($sql); if(mysql_num_rows($get)==0){ echo "Sorry but there is nothing available."; }else{ while ($get_data = mysql_fetch_assoc($get)){ echo $get_data['product_subtotal']; Some more code as requested, I hope this helps! Link to comment https://forums.phpfreaks.com/topic/236634-finding-the-sum-of-a-sum/#findComment-1216486 Share on other sites More sharing options...
fenway Posted May 17, 2011 Share Posted May 17, 2011 Aggregating a SUM usually requires a derived table. Link to comment https://forums.phpfreaks.com/topic/236634-finding-the-sum-of-a-sum/#findComment-1216494 Share on other sites More sharing options...
PapaBurgundy Posted May 17, 2011 Author Share Posted May 17, 2011 Aggregating a SUM usually requires a derived table. I sort of realized that through my trial and error haha but was hoping it would work anyway. Is there actually a way to total a set of returned values from a sum? Link to comment https://forums.phpfreaks.com/topic/236634-finding-the-sum-of-a-sum/#findComment-1216501 Share on other sites More sharing options...
fenway Posted May 17, 2011 Share Posted May 17, 2011 Show me what sample output you're looking for. Link to comment https://forums.phpfreaks.com/topic/236634-finding-the-sum-of-a-sum/#findComment-1216519 Share on other sites More sharing options...
PapaBurgundy Posted May 17, 2011 Author Share Posted May 17, 2011 $sql = "SELECT products.product_id, products.product_price, order_prod.order_quan, products.product_price * order_prod.order_quan AS product_subtotal, SUM(product_subtotal) AS total_order_price"."----------------------------------sum line which doesn't work FROM products, order_prod"." WHERE products.product_id = order_prod.product_id "." AND order_prod.order_id = " . $_GET["order_id"]." ORDER BY products.product_id"; $get = mysql_query($sql); if(mysql_num_rows($get)==0){ echo "Sorry but there is nothing available."; }else{ while ($get_data = mysql_fetch_assoc($get)){ echo $get_data['product_subtotal']; echo $get_data['total_order_price'];-----------------------------total order price echoed here I just want to add up the values of the subtotals of each product. So my product_subtotal would be multiplying the quantity of the product by the price of the product. I then want to add all of those quantity subtotals together to give an order total. So sample output, Product name Quantity Product price Subtotal product name1 1 £350.00 £350.00 product name2 4 £70.00 £280.00 Order total price £630.00 I just want to add together the subtotals to get a total order price. Sorry if my explanation isn't great; my brain has been used and abused this past few weeks. Link to comment https://forums.phpfreaks.com/topic/236634-finding-the-sum-of-a-sum/#findComment-1216542 Share on other sites More sharing options...
fenway Posted May 18, 2011 Share Posted May 18, 2011 Just a second -- I'm confused why you want to do this in the DB? Link to comment https://forums.phpfreaks.com/topic/236634-finding-the-sum-of-a-sum/#findComment-1216767 Share on other sites More sharing options...
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