PHP Sort by using drop-down box

Question

I am basically creating a website and it is a site that sells mobile phones. I need to find a way using PHP to create a drop-down box that can sort the phones by model, brand, screen size etc. (Fields already in my SQL database). What is the simplest way of going about this? I am quite new to PHP and not too sure how to go about it.

Answer 1

You handle sorting in your MySQL queries:

SELECT * FROM <<table>> ORDER BY 'Brand' DESC

and then call the results in your page; you can't re-order the query via javascript (user-side) since the query is called server-side.

Answer 2

You can use $_GET variables to achieve that. Something like this

<?php
  // Let's say that my products category is a $_GET variable
  $category_id = isset($_GET['category_id']) && is_numeric($_GET['category_id']) ? $_GET['category_id'] : 1; // where 1 is a default category to show!
?>

<select onchange="if(this.value != '') document.location = '/my-phones-category.php?category_id=<?php echo $category_id; ?>&order_by=' + this.value">
  <option value="">Choose an option</option>
  <option value="model"<?php if(isset($_GET['order_by']) && $_GET['order_by'] == 'model') echo ' selected="selected"'; ?>>Model</option>
  <option value="brand"<?php if(isset($_GET['order_by']) && $_GET['order_by'] == 'brand') echo ' selected="selected"'; ?>>Brand</option>
</select>

Then we have to see how we can make our query to add the right order

<?php
  switch($_GET['order_by']) {
    case 'model':
      $order_by = " ORDER BY products.product_model";
      break;
    case 'brand':
      $order_by = " ORDER BY products.product_brand";
      break;
    default:
      $order_by = " ORDER BY products.product_price";
  }

  // Now we have the order and we can make the query

  $sql = $mysqli->query("SELECT product_name, product_price 
                         FROM products
                         WHERE category_id='" . $category_id . "'
                         $order_by");
?>

Good luck!