Question

I have a database, called ‘catalog’, and a table, called ‘categories’. The table has 3 columns in this order: categoryId, categoryName, parentCategory. I’m trying to grab categoryId and categoryName for each row that has a parentCategory = ‘root’. I thought it was a straightforward query, but I’m apparently doing something wrong, because I keep getting the message–Couldn’t execute query–but no mysql error is being displayed. I’ve posted my code below. Can anyone point me straight?

P.S. I do have values assigned to the $db variables; I just didn’t include those here.

<?php
$connect = mysqli_connect($db_host,$db_user,$db_password,$db_database)
    or die ("Couldn't connect to server: ".mysqli_error());

function display_children($parent) {
    $query = "SELECT categoryId, categoryName FROM `categories` WHERE parentCategory=".$parent;
    $result = mysqli_query($connect,$query)
        or die ("Couldn't execute query: ".mysqli_error());

    echo "<ul>";
    while ($row = mysqli_fetch_assoc($result)) {
          echo "<li>".$row['categoryName']."</li>";
          display_children($row['categoryId']); 
    }
    echo "</ul>";
    mysqli_close($connect);
}

?>

<div class="menu">    
<?php
    /* Menu Write */
    display_children("root");
?>
</div>

Answer 1

The display_children() function doesn’t have access to the $connect variable.

Try this:

function display_children($parent) {
    global $connect;
    $query = "SELECT categoryId, categoryName FROM `categories` WHERE parentCategory=".$parent;
    $result = mysqli_query($connect,$query)
        or die ("Couldn't execute query: ".mysqli_error());

    echo "<ul>";
    while ($row = mysqli_fetch_assoc($result)) {
          echo "<li>".$row['categoryName']."</li>";
          display_children($row['categoryId']); 
    }
    echo "</ul>";
    mysqli_close($connect);
}