记录不会在android中使用php保存到数据库中

Hi在下面我正在创建群聊应用程序，我正在从客户端使用action=createGroup传递以下详细信息。

java

public String CreateGroup(String groupname,String username,
            ArrayList<FriendInfo> result) throws UnsupportedEncodingException  {
         List<String> usersName = new ArrayList<String>(); 
            for (int i = 0; i < result.size(); i++) { 
            usersName.add(result.get(i).userName); 
            }
                String params = "groupname="+ URLEncoder.encode(groupname,"UTF-8") +
                        "&username="+ URLEncoder.encode(this.username,"UTF-8") +
                        "&password="+ URLEncoder.encode(this.password,"UTF-8") +
                        "&friendUserName=" +usersName+      
                        "&action="  + URLEncoder.encode("CreateGroup","UTF-8")+
                        "&";
            Log.i("PARAMS", params);
            return socketOperator.sendHttpRequest(params);

这是我的服务器端代码。我在哪里犯了错误，因为数据没有保存到数据库中。有人能帮我吗

php

   case "CreateGroup":
    $userId = authenticateUser($db, $username, $password);
    if ($userId != NULL)
    {
        if (isset($_REQUEST['friendUserName']))         
        {               
             $friendUserNames = $_REQUEST['friendUserName'];
            $friendUserNames = str_replace('[','',$friendUserNames);
            $friendUserNames = str_replace(']','',$friendUserNames);
            $friendUserNames = explode(",", $friendUserNames);
            foreach($friendUserNames as $friendUserName){
             $groupname = $_REQUEST['groupname'];
             $sql = "select Id from users where username='$friendUserName' limit 1";
             echo $sql;
             if ($result = $db->query($sql))
             {
                    if ($row = $db->fetchObject($result))
                    {
                         $requestId = $row->Id;
                         $groupname = $row->Id;
                         if ($row->Id != $userId)
                         {
                                 $sql = "insert into group (groupname,providerId, requestId)values(".$groupname.",".$userId.",".$requestId.")";
                                 echo $sql;

                                 if ($db->query($sql))
                                 {
                                        $out = SUCCESSFUL;
                                 }
                                 else
                                 {
                                        $out = FAILED;
                                 }
                        }
                        else
                        {
                            $out = FAILED;  
                        }                                                
                    }
                    else
                    {
                        $out = FAILED;                      
                    }
             }
             else
             {
                    $out = FAILED;
             }              
        }
        }
        else
        {
                $out = FAILED;
        }           
    }
    else
    {
        $out = FAILED;
    }   
break;

表格

CREATE TABLE IF NOT EXISTS `group` (
`id` int(11) NOT NULL,
  `groupname` varchar(25) NOT NULL,
  `providerId` int(25) NOT NULL,
  `requestId` int(5) NOT NULL
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=5 ;
--
-- Indexes for dumped tables
--
--
-- Indexes for table `group`
--
ALTER TABLE `group`
 ADD PRIMARY KEY (`id`), ADD UNIQUE KEY `username` (`providerId`), ADD UNIQUE KEY `userid` (`providerId`), ADD UNIQUE KEY `ufriendid` (`requestId`);