Filter Product option in php

Question

I am trying to create an e-commerce website and on my products page, I want to be able to sort the products by categories (eg mens, women, children etc). I have managed to make the category names show up dynamically in the filter option.. But I dont know how to get the "apply" button to work. So once I pick the category and click apply it redirects me to a page showing only those products that are in a selected category.

Here is the code I have used:

function get_categories_new(){
    $query = query("SELECT * FROM categories");
    confirm($query);

    while($row = fetch_array($query)) {
        $categories_links = <<<DELIMETER
            "<option> {$row['cat_title']}</option></a>"
            DELIMETER;
        echo $categories_links;
    }
}

I am then calling the function in the products page. Like this:

<!-- FILTER -->
    <section class="module-small">
        <div class="container">
            <form class="row">
                <div class="col-sm-3 m-b-sm-20">
                    <select class="form-control">
                        <option selected="selected"> Choose Category</option>
                        <?php get_categories_new(); ?>
                    </select>
                </div>
               <div class="col-sm-3">
                   <button type="submit" class="btn btn-block btn-round btn-g">Apply</button>
                </div>
            </form>
        </div>
    </section>
<!-- /FILTER -->

Answer 1

Use form action to some target page and get the user submitted data via GET method. Then do the filteration. 1. form action="products-filter.php" in form tag add action tag ex. to "products-filter.php" 2. select class="form-control" name="category" in select dropdown add the name as "category". Using this we will retrieve the data and do the filteration.

products-filter.php code

<?php
function get_products_by_category($category_name = ''){
    $query = query("SELECT * FROM products where category_name ='$category_name'");
    echo "<table>";
    while($row = fetch_array($query)) {
       echo "<tr><td>".$row['product_name']."</td></tr>";
    }
    echo "</table>";
}
get_products_by_category(add_slashes($_GET['category']));
?>