mongodb - 这个 mongo 查询有什么问题？

Question

db.items.mapReduce({function(){emit(this.name,this.price);},function(key,value){Array.sum(value)},{out:"map_reduce_example"}});

项目是：

{  
   "_id":"5bfe309ff0e3775c684e85c9",
   "name":"sdgjkld",
   "price":"123"
}

错误描述：

2018-11-28T12:16:19.407+0530 E QUERY [thread1] SyntaxError: invalid property id @(shell):1:98

标签： mongodbmongodb-query

Answer 1

试试这个

db.items.mapReduce(
    function () {
        emit(this.name, this.price);
    },
    function (key, value) {
        Array.sum(value)
    },
    { out: "map_reduce_example" }
)

或者

var first = function () {
    emit(this.name, this.price);
}
var second = function (key, value) {
    Array.sum(value)
}

db.items.mapReduce(
    first,
    second,
    { out: "map_reduce_example" }
)