有数据库结构如下：

集合MessageList：

{
    _id: "id1",
    manage_id: "userid_3",
    member_idList: [
        "userid_1", "userid_2"
    ]
}

集合 UserList：

{
    _id: "userid_1",
    Name: "张三"
}, {
    _id: "userid_2",
    Name: "李四"
}, {
    _id: "userid_3",
    Name: "王五"
}, {
    _id: "userid_4",
    Name: "测试用户"
},

想要实现的是查询后输出：

{
    _id: "MessageList的_id"
    manage: {
        _id: "userid_3",
        Name: "王五"
    },
    member_idList: [{
        _id: "userid_1",
        Name: "张三"
    }, {
        _id: "userid_2",
        Name: "李四"
    }]
}

求教各位大神帮忙啊~~