PHP Update always update empty string - php

Question

let me explain the code I'm getting data from the db and display the data in text input then when the user make changes I get the user input and update the table however when it update it update to empty data
<?php
echo "<form action='' method='get'>";
echo "<td class='data'><input type='product_name' id='product_name' value=" . $row['product_name'] . "> </td>";
echo "<td class='data'><input type='products_price' id='products_price' value=" . $row['products_price'] . "> </td>";
echo "<td class='data'><input type='products_desc' id='products_desc' value=" . $row['products_desc'] . "> </td>";
echo "</form>";
echo "</tr>";
echo "</table>";
echo "<form action='' method='POST'>
<input name='update' type='submit' value='Update' style='margin-left: 720px'>
</form>";
$product_name = isset($_GET['product_name']) ? $_GET['product_name'] : '';
$products_desc = isset($_GET['products_desc']) ? $_GET['products_desc'] : '';
$products_price = isset($_GET['products_price']) ? $_GET['products_price'] : '';
if (isset($_POST["update"])) {
$sql1 = "UPDATE tbl_products SET products_desc='" . $products_desc . "',product_name='" . $product_name . "',products_price='" . $products_price . "' WHERE products_id='" . $product_id . "'";
mysqli_query($conn, $sql1) or die(mysqli_error($conn));
echo "yess";
}
?>

Answer 1

Your input elements have no name attribute, so things like $_GET['product_name'] will always be empty. The name attribute is the key in the key/value pair sent to the server.
Additionally, the type attributes are all broken. (Though I suspect the browser is automatically "correcting" that by defaulting to a text input.)
Add the name attribute (and fix type):
<input type='text' name='product_name' id='product_name' ...
Additionally, you have two forms. So when you click your button, that form doesn't submit any of the inputs. Because they're in a different form.
Put them all into the same form, and decide whether you want to use GET or POST (since your server-side code is going to need to know that).

Answer 2

You defined your data form in one form tag and submit form in the another form tag:
<form action='' method='POST'>
<input name='update' type='submit' value='Update' style='margin-left: 720px'>
</form>
echo "<form action='' method='get'>";
echo "<td class='data'><input type='product_name' id='product_name' value=" . $row['product_name'] . "> </td>";
echo "<td class='data'><input type='products_price' id='products_price' value=" . $row['products_price'] . "> </td>";
echo "<td class='data'><input type='products_desc' id='products_desc' value=" . $row['products_desc'] . "> </td>";
echo "</form>";
When you submit your first form but your data is on another form
this is what is wrong