Post query from php to sqlite database through button - php

Question

So I have the following webpage containing html and php. Within the page I have a checkbox which populates its options from a table within the database. and another multi-select checkbox that gets populated from a different table. The first checkbox is related to products and the second is store location which can have multiple locations.
I'm trying to setup a submit button after something is selected from both it posts to the database within the table to give store location details for each product.
table schema:
table name: products
id, name, StoreLocation
table name: stores
id, name
how I am using the product checkbox
<select name="Pname">
<?php
$resultSet = $db->query('SELECT name FROM products');
while($row = $resultSet->fetchArray()){
echo"<option value=\"productN\">" . $row['name'] . "</option>";
}
?>
</select>
store location checkbox
<select name="Sname", id="Sname" multiple>
<?php
$resultSet = $db->query('SELECT name FROM stores');
while($row = $resultSet->fetchArray()){
echo"<option value=\"storeN\">" . $row['name'] . "</option>";
}
?>
</select>
This is what I was attempting but it did not work
<form action="index.php" method="post">
<input type="submit" name="myButton" value="Submit"/>
<?php
$query = "INSERT INTO products (Store Location) VALUES ($row)";
?>
</form>
Is it a problem with my setup for the sql query? When I try to use the submit button nothing is inserted to the database. I've tried sample queries and those did not work either.

Answer 1

First: all options have the same value. You should be using the id of the record, so you can identify it, when the FORM is posted.
echo"<option value=\"productN\">" . $row['name'] . "</option>";
Second: This makes no sense
<form action="index.php" method="post">
<input type="submit" name="myButton" value="Submit"/>
<?php
$query = "INSERT INTO products (Store Location) VALUES ($row)";
?>
</form>
If you want to react on a POST request (FORM submit) you'll receive the data of the FORM in PHP via $_POST. In this array, check for the name of your Submit button. For beginners it's helpful to dump the POST array, to see what it contains: var_dump($_POST);
Lastly: Do never pass data directly into SQL queries, use prepared statements.
Consider to make some tutorials about Webdevelopment with PHP.