Question

I am only able to echo the first selectbox but not the sub category. I checked the code for syntax errors and there were none found. I am guessing the logic is incorrect. Can anyone tell me Why is it not displaying the subcategories select box ?

   <?php 

    $dbh = new PDO("mysql:host=" . $host . ";dbname=" . $db, $user, $pass);

    if(isset($_GET["category"]) && is_numeric($_GET["category"]))
    {
        $category = $_GET["category"];
    }


    ?>


    <form name="theForm" method="get">

        <!-- Category SELECTION -->

   <select name="category" size="6" onChange="autoSubmit();">
                <?php
        $categories = $dbh->query('SELECT * FROM category ORDER BY c_id');

        while ($row = $categories->fetch()) {
        echo '<option value="' . $row['c_id'] . '"';
        if ($row['c_id'] == $category) echo ' selected';
        echo '>' . htmlentities($row['category']);
      }
                ?>
   </select>

        <br><br>



    </form>

Answer 1

Your query is most likely returning 0 results due to your use of a variable inside of a string using single quotes.

$subcategories = $dbh->query('SELECT s_id, subcategory FROM subcategory Where c_id = $category');

Use double quotes around your query, or concatenate the value like '... c_id = ' . $category

But even better than that, learn how to use parameterized queries and bind the values instead.