Display all mysql table fields with PHP

1. How to display all mysql table field names.
2. Show all mysql table field name with php.
3. List all field names of mysql table.

This script lists all mysql table field names.

Script

$i=0;
$sql = mysql_query("select * from products");

while( $i < mysql_num_fields($sql)){

    echo mysql_field_name($sql, $i)  .  ', ';
    $i++;
}

Output

id, product, ,item_code, category, price