php获取mysql表中所有字段名到一个数组

$conn=mysql_connect("localhost","root","");
mysql_select_db("ceshi",$conn);
$sql="select * from price";
$result = mysql_query($sql);
for ($i=0;$i<mysql_num_fields($result);$i++){
    echo $name = mysql_field_name($result,$i).'';
}