Como obter os nomes das colunas junto com o conjunto de resultados em php/mysql?

<?php
$dbLink = mysql_connect('localhost', 'usr', 'pwd');
mysql_select_db('test', $dbLink);

$sql = "SELECT * FROM cartable";
$result = mysql_query($sql) or die(mysql_error());

// Print the column names as the headers of a table
echo "<table><tr>";
for($i = 0; $i < mysql_num_fields($result); $i++) {
    $field_info = mysql_fetch_field($result, $i);
    echo "<th>{$field_info->name}</th>";
}

// Print the data
while($row = mysql_fetch_row($result)) {
    echo "<tr>";
    foreach($row as $_column) {
        echo "<td>{$_column}</td>";
    }
    echo "</tr>";
}

echo "</table>";
?>