mongoose 外键查询问题

[Chan66]

有两个表，一个用户表，一个订单表，现在想要查询所有 appId 为 1 的用户的订单应该怎么查询呢

const orderSchema = new mongoose.Schema({
    user: {
        type: mongoose.SchemaTypes.ObjectId,
        ref: "User",
        required: true
    },
    orderNum: {
        type: String,
        required: true
    },
})

const UserSchema = new mongoose.Schema({
    nickname: String,
    avatarUrl: String,
    phone: String,
    appId: {
        type: String,
    }
});

[dreasky]

aggregate $lookup

[leopod1995]

最简单的

1. 先查所有 appId 为 1 的用户 id -> userIds = user.find({ appId: 1 }).select('_id')
2. order.find({ user: { $in: userIds }})