mysql - Eloquent 查询构建复杂查询以获取在同一表的 2 个不同列中搜索 ID 的唯一记录

Question

我正在将一个项目迁移到 Laravel 4，但我遇到了一个相当复杂的查询，我想将其迁移到正确的 Eloquent 查询中。

我有一个包含聊天消息的表，名为 chat_messages ，带有表示模型 Chatmessage

该表包含一个发送者列和一个接收者列，其中的用户 ID 链接到 users 表和 User 模型。

在旧版本应用程序上使用原始 SQL 获取包含所有聊天伙伴的所有用户 ID 的列表的查询如下:

$sql_allChatPartners = "SELECT DISTINCT chatPartner   
FROM ( SELECT * FROM (
    SELECT cm_receipient AS chatPartner, cm_sent_at
    FROM chat_messages WHERE cm_sender = '".$me->userID."'
    UNION
    SELECT cm_sender AS chatPartner, cm_sent_at
    FROM chat_messages WHERE cm_receipient = '".$me->userID."'
) whateva ORDER BY whateva.cm_sent_at DESC ) other";

很抱歉将“假”表命名为whateva和其他:-)

有人能给我正确的方向来使用 Eloquent Querybuilder 执行此操作吗？

重要的是，我必须以正确的顺序获取 chatPartner ID 列表，其中最后一条聊天消息已作为第一个 chatPartner 进行交换。聊天中不活动时间最长的聊天伙伴作为最后一个条目。

这是我迄今为止在用户模型中得到的......

public function allopenchats(){
 $asSender = Chatmessage::where('sender', $this->id)->select('receipient as chatPartner, created_at');
 $asBoth = Chatmessage::where('receipient', $this->id)->select('sender as chatPartner, created_at')
              ->union($asSender)->orderBy('created_at', 'desc')->get();
}

我将列 cm_receipient 重命名为 receipient，将 cm_sender 重命名为 sender 和 sent_at > 到新版本的新数据库中的created_at

非常感谢您的帮助!

Answer 1

您的sql可能会更改为:

    SELECT IF (cm_receipient = '10', cm_sender, IF (cm_sender = '10',cm_receipient, 'no')) AS chatPartner, cm_sent_at
FROM chat_messages
WHERE cm_receipient = '10' OR cm_sender = '10'
GROUP BY chatPartner
HAVING chatPartner != 'no'

按 cm_sent_at DESC 排序

正常情况下:

Chatmessage::where('sender','=',$this->id)
    ->orWhere('receipient','=',$this->id)
    ->select(DB::raw('IF (receipient = '.$this->id.', sender, IF (sender = '.$this->id.',receipient, 'no' )) AS chatPartner'), 'created_at')
    ->groupBy('chatPartner')
    ->having('chatPartner', '!=', 'no')
    ->orderBy('created_at', 'desc')
    ->get();