MongoDB填充聚合展开

Question

我的用户模型有以下数据结构：

{
 _id: object,
 name: string,
 quotes: [ { quote: string, createdAt: date } ],
 friends: [ { _id: object } ] (this refers to the _id from the user model)
}

我想做的是回复：

{
  quote: string,
  createdAt: date,
  _id: object (friend's)
}
{
  quote: string,
  createdAt: date,
  _id: object (friend's)
}
...

按createdAt = recent排序到最早

Answer 1

我从你的问题中理解你想要根据最近的时间解开两个数组元素。

db.user.aggregate([
    {
        $unwind: "$quotes"
    },
    {
        $unwind: "$friends"
    },
    {
        $sort: {
            "quotes.createdAt": -1
        }
    }
])