Question

好的，我想将查询从MySQL转换成MongoDB，因为我需要它来优化我的数据，但是到目前为止我什么都没做...

MySQL查询

SELECT notifications.entity_id 
FROM notifications
INNER JOIN discussions
ON notifications.entity_id = discussions._id 
WHERE notifications.subscribers = 1

无论我尝试什么，我似乎都无法接近JOIN另一个表...我已经在PHP中以简单的方式完成了该操作，但是由于优化不足或没有优化，这会引起很多麻烦... < / p>

public function getData($userId) {

    $wheres =   ['subscribers' => $userId];
    $data   =   $this->get($wheres, ['entity_id']); # works for notifications table that I have predefined for this function

    $wheres =   ['_id' => $data['_id']];
    $data  =   $this->get_discussions($wheres, []); #queries discussions table

    return $data;
}

Answer 1

我对此mysql查询的解决方案是

db.notifications.aggregate({
    {$match : {subscribers : 1}},
    $lookup:{
        from:"discussions",
        localField:"entity_id",
        foreignField:"id",
        as:"entityids"
    },
    { "$unwind": "$entityids" }
})

在mongo shell上运行此命令。您也可以使用php方法在PHP代码中触发此操作。希望对您有帮助。

用PHP内部连接到mongoDB

1 个答案: