<?phpheader("Content-type: text/html; charset=utf-8");if(!empty($_POST['username'])){$name=$_POST['username'];}if(!empty($_POST['pwd'])){$pwd=$_POST['pwd'];}function sqlDql($name,$pwd){$conn=mysql_connect("localhost","root","root");if(!$conn){die("連接失敗".mysql_error());}mysql_select_db("test",$conn) or die(mysql_error());//設置字符集mysql_query("set names utf8");$sql="select * from zhuche;";$res=mysql_query($sql,$conn) or die(mysql_error());while($row=mysql_fetch_row($res)){if($name==$row[1]){echo "用戶名已經存在<br/>";echo "<a href='login.php'>返回注冊頁面</a>";// die(mysql_free_result($res)."連接".mysql_close($conn));mysql_free_result($res);mysql_close($conn);exit();}}$sql2="insert into zhuche (Username,password) values ('".$name."','".$pwd."');";$res2=mysql_query($sql2,$conn) or die(mysql_error());echo "<table border='1px solid black'>";echo "<tr><td>序號</td><td>用戶</td><td>密碼</td></tr>";while($row=mysql_fetch_row($res)){echo "<tr>";foreach($row as $key=> $val){echo "<td>--".$val."</td>";}echo "</tr>";}echo "</table>";mysql_free_result($res);mysql_close($conn);}sqlDql($name,$pwd);?>如果在第一個while沒有退出 為什么下面的$res去不出數據？輸出結果是