Category - Products [PHP , MySQL PDO]

Question

This is my category & products SQL/PHP schema.

I need to echo the <hr> for each of my categories and not for each products . This is my code :

$sql = $db->query("SELECT * from cat,products where cat.cat_id = products.cat_id order by products.cat_id desc");
while ($row = $sql->fetch(PDO::FETCH_ASSOC)){   
    $ID = $row["id"];
    $Title = $row["title"];
    $CatID = $row["cat_id"];

    $row["cat_id"] = $row["cat_name"];
    switch ($row["cat_id"]){
        case $row["cat_id"] == $row["cat_name"]:
            echo "<hr>";
            break;
        default:

            break;
    }

    echo $row["cat_id"];
    echo "<a href='test.php?cat=$CatID&prod=$ID'>$Title</a><br/>";
}

Image :

thanks and sorry for my poor English...

Answer 1

You can write the following due to the fact that your SQL statement is sorted by the categories:

        $tmp_category = '';    

            $sql = $db->query("SELECT * from cat,products where cat.cat_id = products.cat_id order by products.cat_id desc");
                while ($row = $sql->fetch(PDO::FETCH_ASSOC)){  


                $ID = $row["id"];
                $Title = $row["title"];
                $CatID = $row["cat_id"];

    if ($row["cat_id"] <> $tmp_category){ //you can use  != instead of <> as well

        $tmp_category = $row["cat_id"]; 
        echo "<hr>";        
        echo $row["cat_id"];
        echo "<a href='test.php?cat=$CatID&prod=$ID'>$Title</a><br/>";

    }
    else
    {

        echo $row["cat_id"];  // this is optional, you can delete the cat ID from here and it will show you only the above link.
        echo "<a href='test.php?cat=$CatID&prod=$ID'>$Title</a><br/>";
    }


        }