php - mysqli_fetch_assoc dies on first row -

i have following table in mysql:

╔══════╦════╗
║... city.....║...zip..║
╠══════╬════╣
║ prague. ║ 11000║
║ brno..... ║ 34785║
╚═══════════╝

the following code works:

class mysql{   function connect(){     $this->c = new mysqli(       $this->option['dbhost'],       $this->option['dbuser'],       $this->option['dbpass'],       $this->option['dbname']     );     if($this->c->connect_errno){       exit("connect failed: ".$this->c->connect_error);     }     if(!$this->c->select_db($this->option['dbname'])){       exit("cannot select database: ".$this->option['dbname']);     }   }   function query($query){     if(!$this->c->query($query)){       exit("cannot execute query: {$query}<br>mysql error: {$this->c->error}<br>mysql error code: {$this->c->errno}");     }     return $this->c->query($query);   }   function fetch_assoc($result){     return $result->fetch_assoc();   } }  $db = new mysql; $db->connect(); $query = $db->query("select city, zip cities"); while($row = $db->fetch_assoc()){   print_r($row); } 

the code works until try change fetch_assoc part this:

  function fetch_assoc($query){     $result = $this->query($query);     return $result->fetch_assoc();   } }  $db = new mysql; $db->connect(); while($row = $db->fetch_assoc("select city, zip cities")){   print_r($row); } 

in case endlessly (stopped max execution time) prints first row of table: array ( [city] => prague [zip] => 11000 )

i believe should it, making query once , iterating on mentioned in comments above:

$db = new mysql; $db->connect(); $query = $db->query("select city, zip cities"); $result = $db->fetch_assoc(); while ($row = $result->fetch_assoc()) print_r($row);