一个函数问题

$host=mysqli_connect("hostname","username","password");
            mysqli_select_db($host,"db_name");
           $query='select *from 表名';
           $result=mysqli_query($host,$query)
          while($rows=mysqli_fetch_row($result))
               {
                echo $rows[0].",".$rows[1].",".$rows[2].",".$rows[3]."<br>";
               }