Create foreach for a value that exists twice - php

Question

I have the following statement which SELECTs ProductName and Quantity from the orderDetails table. See below:
try {
$stmt = $conn->prepare("SELECT ProductName, Quantity FROM orderDetails WHERE OrderID = :OrderID");
$stmt->bindParam(':OrderID', $_SESSION['newOrderID'], PDO::PARAM_INT);
$stmt->execute();
$_POST['ProductName'] = $stmt->fetch(PDO::FETCH_ASSOC);
}
catch(PDOException $e) {
echo "Error: " . $e->getMessage();
}
If $_POST['ProductName']['ProductName'] exists more than once how can I create a foreach loop based on that?
What I have tried so far...
foreach($_POST['ProductName']['ProductName']) {
}
This did not work...
What have I done wrong?
Complete Code:
try {
$stmt = $conn->prepare("SELECT ProductName, Quantity FROM orderDetails WHERE OrderID = :OrderID");
$stmt->bindParam(':OrderID', $_SESSION['newOrderID'], PDO::PARAM_INT);
$stmt->execute();
array_push($_POST["ProductName"], $stmt->fetch(PDO::FETCH_ASSOC));
}
catch(PDOException $e) {
echo "Error: " . $e->getMessage();
}
// echo $_POST['ProductName']['ProductName'];
// echo $_POST['ProductName']['Quantity'];
try {
$stmt1 = $conn->prepare("SELECT Stock FROM products WHERE ProductName = :ProductName");
$stmt1->bindParam(':ProductName', $_POST['ProductName']['ProductName']);
$stmt1->execute();
$_POST['Stock'] = $stmt1->fetch(PDO::FETCH_ASSOC);
}
catch(PDOException $e) {
echo "Error: " . $e->getMessage();
}
// echo $_POST['Stock']['Stock'];
$_POST['DEDUCT'] = $_POST['Stock']['Stock'] - $_POST['ProductName']['Quantity'];
try {
$stmt2 = $conn->prepare("UPDATE products SET Stock = :Stock WHERE ProductName = :ProductName");
$stmt2->bindParam(':Stock', $_POST['DEDUCT']);
$stmt2->bindParam(':ProductName', $_POST['ProductName']['ProductName']);
$stmt2->execute();
}
catch(PDOException $e) {
echo "Error: " . $e->getMessage();
}

Answer 1

You can make a new array called (for example, $rows) which contains all of the fetched data using the function fetchAll() (fetch() only retrieves the next one row).
The most straightforward way to do this is as follows:
try {
$stmt = $conn->prepare("SELECT ProductName, Quantity FROM orderDetails WHERE OrderID = :OrderID");
$stmt->bindParam(':OrderID', $_SESSION['newOrderID'], PDO::PARAM_INT);
$stmt->execute();
//Add all returned values to an array called "$rows"
$rows = $stmt->fetchAll(PDO::FETCH_ASSOC);
}
catch(PDOException $e) {
echo "Error: " . $e->getMessage();
}
Then if you want to access that data later you can do:
foreach($rows as $row){
var_dump($row); //Show the data in the row to double-check
}

Answer 2

You can create array using foreach like this :
$newval_arr = array();
foreach($_POST['ProductName']['ProductName'] as $key=>$value) {
if(!in_array($value,$newval_arr) || empty($newval_arr))
{
$newval_arr[] = $value;
}
}
Then after you can use $newval_arr in foreach
foreach($newval_arr as $key=>$value)
{
//Your code herer
}