为何mysql_fetch_array/assoc + foreach只能遍历一条记录

foreach(mysql_fetch_array($result) as $key=>$row){
							
					 	print_r($row);
									
				} 

while($row=mysql_fetch_array($result)) 
{ 
       $rows[]  = $row; 
} 

foreach($rows as $k => $v) 
{ 
   foreach($v as $vv){
     echo $vv;
   }