使用内爆从联接表上的mysql_query生成csv文件，输出会给出重复的字段

$result = mysql_query("SELECT n.sbjnum, n.scan_no, d.name, d.tel_c, d.srvyr
                       FROM no_scans AS n 
                   JOIN details AS d ON n.sbjnum = d.sbjnum ");             
while ($row = mysql_fetch_array($result)) {
  echo $string1 = implode(" , ",$row) . "<br />";
}