未定义的变量

Question

你好，我有一个错误的脚本，我不知道为什么，但变量定义：

public function Updates($user_ids,$lastid) { 
    if($lastid==0) { 
     $loadmore = "";  
    }else{ 
     $loadmore = " AND M.msg_id < $lastid "; 
    } 

public function Total_Updates($user_ids) 

{ 

$sql = "SELECT M.msg_id, M.uid_fk, M.message, M.created, U.fname, U.lname, M.uploads, M.profile_uid FROM messages M, users U WHERE M.uid_fk=U.uid AND M.uid_fk IN ($user_ids) $loadmore 
     UNION 
     SELECT M.msg_id, M.uid_fk, M.message, M.created, U.fname, U.lname, M.uploads, M.profile_uid FROM messages M, users U WHERE M.uid_fk=U.uid AND M.profile_uid IN ($user_ids) $loadmore ORDER BY msg_id DESC "; 

     $query = mysqli_query($db_conx, $sql); 
     $data = mysqli_num_rows($query); 
     exit(); 

    return $data; 

} 

，undefined是坐落在同一行选择变量.. 我在等待您的帮助。谢谢

Answer 1

你有2线，SELECT，但是两者都具有相同的变量：$ user_ids和$ loadmore

错误消息应显示什么是警告有关。但是$ user_ids看起来是正确声明的，所以这会留下$ loadmore。

它也看起来function Total_Updates是在function Updates？

如果它是一个单独的函数（并且只是一个复制粘贴错误？），您可能只想在两个函数的开头都使用global $loadmore;。

编辑：
代码使用全局可能的更改。使用此功能Updates，始终需要在Total_Updates之前调用。

public function Updates($user_ids, $lastid) 
{ 
    global $loadmore; // Keep available for Total_Updates 

    if($lastid==0) { 
     $loadmore = "";  
    }else{ 
     $loadmore = " AND M.msg_id < $lastid "; 
    } 
    $db_conx = mysqli_connect("localhost", "root", "", "test"); 
    $sql = "SELECT M.msg_id, M.uid_fk, M.message, M.created, U.fname, U.lname, M.uploads, M.profile_uid FROM messages M, users U WHERE M.uid_fk=U.uid AND M.uid_fk IN ($user_ids) $loadmore 
      UNION 
      SELECT M.msg_id, M.uid_fk, M.message, M.created, U.fname, U.lname, M.uploads, M.profile_uid FROM messages M, users U WHERE M.uid_fk=U.uid AND M.profile_uid IN ($user_ids) $loadmore ORDER BY msg_id DESC LIMIT " .$this->postcount; 
    $query = mysqli_query($db_conx, $sql);  

    while($row = mysqli_fetch_array($query, MYSQLI_ASSOC)){ 
     $data[]=$row; 
     return $data; 
    } 
} 

public function Total_Updates($user_ids) 
{ 
    global $loadmore; // From Updates 

    $db_conx = mysqli_connect("localhost", "root", "", "test"); 

    $sql = "SELECT M.msg_id, M.uid_fk, M.message, M.created, U.fname, U.lname, M.uploads, M.profile_uid FROM messages M, users U WHERE M.uid_fk=U.uid AND M.uid_fk IN ($user_ids) $loadmore 
      UNION 
      SELECT M.msg_id, M.uid_fk, M.message, M.created, U.fname, U.lname, M.uploads, M.profile_uid FROM messages M, users U WHERE M.uid_fk=U.uid AND M.profile_uid IN ($user_ids) $loadmore ORDER BY msg_id DESC "; 

    $query = mysqli_query($db_conx, $sql); 
    $data = mysqli_num_rows($query); 
    exit(); // This is just for test? it disables return. 
    return $data;  
} 

一种替代的解决方案是创建用于loadmore前一个单独的函数：

public function getUpdates_loadmore($lastid) 
{ 
    if($lastid==0) return ""; 
    return " AND M.msg_id < $lastid "; 
} 

而对于此$ lastid参数将需要被加入到function Total_Updates($user_ids) =>function Total_Updates($user_ids, $lastid)

Answer 2

做 $loadmore = getUpdates_loadmore($lastid);

实际上，我的脚本看起来完全一样：

public function Updates($user_ids,$lastid) 
{ 
if($lastid==0) { 
    $loadmore = "";  
}else{ 
    $loadmore = " AND M.msg_id < $lastid "; 
} 
    $db_conx = mysqli_connect("localhost", "root", "", "test"); 
    $sql = "SELECT M.msg_id, M.uid_fk, M.message, M.created, U.fname, U.lname, M.uploads, M.profile_uid FROM messages M, users U WHERE M.uid_fk=U.uid AND M.uid_fk IN ($user_ids) $loadmore 
      UNION 
      SELECT M.msg_id, M.uid_fk, M.message, M.created, U.fname, U.lname, M.uploads, M.profile_uid FROM messages M, users U WHERE M.uid_fk=U.uid AND M.profile_uid IN ($user_ids) $loadmore ORDER BY msg_id DESC LIMIT " .$this->postcount; 
    $query = mysqli_query($db_conx, $sql);  

    while($row = mysqli_fetch_array($query, MYSQLI_ASSOC)){ 
    $data[]=$row; 
    return $data; 
    } 
}   
    public function Total_Updates($user_ids) 

{ 

     $db_conx = mysqli_connect("localhost", "root", "", "test"); 

$sql = "SELECT M.msg_id, M.uid_fk, M.message, M.created, U.fname, U.lname, M.uploads, M.profile_uid FROM messages M, users U WHERE M.uid_fk=U.uid AND M.uid_fk IN ($user_ids) $loadmore 
     UNION 
     SELECT M.msg_id, M.uid_fk, M.message, M.created, U.fname, U.lname, M.uploads, M.profile_uid FROM messages M, users U WHERE M.uid_fk=U.uid AND M.profile_uid IN ($user_ids) $loadmore ORDER BY msg_id DESC "; 

     $query = mysqli_query($db_conx, $sql); 
     $data = mysqli_num_rows($query); 
     exit(); 
    return $data;  
} 

在第一个$ sql中，变量$ loadmore正确运行，但在第二个$ sql中不起作用。我一直同样的错误：

Notice: Undefined variable