Get quantity of certain product from database instead of session - Shopping Cart (PHP & MySQL)
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I have been trying to create a persistent MySQL-based shopping cart application starting from a session-based php shopping cart. Thecart table has the structureuserid | productid | quantity | postingdate.
In the session-based implementation, the quantity info for a certain product was stored in$_SESSION['cart'][$row['id']]['quantity'];; I am facing trouble with retrieving the quantity info for a certain product from thecart table in the database because I can't seem to find how to extract theproductId necessary for the$getquantity query.
$sql1 = "SELECT * FROM cart WHERE userid='$userId'"; //selects the user's cart
$query1=mysqli_query($con,$sql1);
if (!empty($query1)) { //if the user's cart isn't empty
while($row = mysqli_fetch_array($query1)){
$query = mysqli_query($con,"SELECT * FROM products JOIN cart ON cart.productid=products.id
ORDER BY cart.postingDate DESC"); //selects all the products in the current user's cart
}
$totalprice=0;
$totalqunty=0;
if (!empty($query)) {
while ($row = mysqli_fetch_array($query)) { //for each product
//$quantity=$_SESSION['cart'][$row['id']]['quantity']; //SESSION IMPLEMENTATION
$id = $row['id'];
$quantity = mysqli_query($con,"SELECT quantity FROM cart WHERE userid='$userId' AND productid='$id'"); //MY IMPLEMENTATION, THE WRONG PART IS WITH $id
$subtotal= $quantity*$row['productPrice']+$row['shippingCharge'];
$totalprice += $subtotal;
$_SESSION['qnty']=$totalqunty+=$quantity; //SESSION IMPLEMENTATION
}
}
}
I've tried$row['id'] but it returns an array of all theproductid from the records returned by$query and MySQl doesn't seem to accept it, while instead I need the$getquantity to run on eachproductid. Please don't mind how it's vulnerable to SQL injections as I will get to that in later stages.
Answer
Solution:
Here's a working solution: I could have just selected thecart.quantity attribute (considering how theproducts andcart table were joined):
$sql1 = "SELECT * FROM cart WHERE userid='$userId'"; //selects the user's cart
$query1=mysqli_query($con,$sql1);
if (!empty($query1)) { //if the user's cart isn't empty
while($row = mysqli_fetch_array($query1)){
$query = mysqli_query($con,"SELECT products.productImage1 , products.productName ,
products.id, cart.productId, cart.quantity as qty, products.productPrice,
products.shippingCharge FROM products JOIN cart ON cart.productid=products.id
ORDER BY cart.postingDate DESC"); //selects all the products in the current user's cart
}
$totalprice=0;
$totalqunty=0;
if (!empty($query)) {
while ($row = mysqli_fetch_array($query)) { //for each product
$quantity=$row['qty'];
$subtotal= $quantity*$row['productPrice']+$row['shippingCharge'];
$totalprice += $subtotal;
}
}
}
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