“Notice: Undefined variable: db” when using PDO [closed]

Answer 1

The $db object doesn't exist in the context of the function. You should pass it to the function as an additional parameter.

function GetCategory($db)
{
    $sql = 'SELECT * FROM category ORDER BY order_cat DESC';
    foreach ($db->query($sql) as $row)
    {
        echo "$row[name]
";
    }
}

And read up on variable scope.