mongodb - 无法在聚合管道上从 BSON 类型字符串转换为 Date

Question

我使用的是 MongoDB 3.4.9，我想要月度报告 w.r.t.客户信息，这里是带有嵌套项目和收到错误的示例示例 mongodb 记录是:

can't convert from BSON type string to Date

    {
"_id" : ObjectId("59da6a331c7a9ac0b6674fe8"),
"date" : ISODate("2017-10-08T18:10:59.899Z"),
"items" : [ 
    {
        "quantity" : 1,
        "price" : 47.11,
        "desc" : "Item #1"
    }, 
    {
        "quantity" : 2,
        "price" : 42.0,
        "desc" : "Item #2"
    }
],
"custInfo" : "Tobias Trelle, gold customer"
  }

{
"_id" : ObjectId("59da6a511c7a9ac0b6674fed"),
"date" : ISODate("2017-10-08T18:11:28.961Z"),
"items" : [ 
    {
        "quantity" : 1,
        "price" : 47.11,
        "desc" : "Item #1"
    }, 
    {
        "quantity" : 2,
        "price" : 42.0,
        "desc" : "Item #2"
    }
],
"custInfo" : "Tobias Trelle, gold customer"
  }

  {
"_id" : ObjectId("59da6a511c7a9ac0b6674ff0"),
"date" : ISODate("2017-10-08T18:11:29.133Z"),
"items" : [ 
    {
        "quantity" : 1,
        "price" : 47.11,
        "desc" : "Item #1"
    }, 
    {
        "quantity" : 2,
        "price" : 42.0,
        "desc" : "Item #2"
    }
],
"custInfo" : "Tobias Trelle, gold customer"
  }

这是按 custInfo month wise 计算总和分组的 MongoDB 查询

db.runCommand({aggregate:"order", pipeline : 
[{$match : {$and : [{"date" : {$gte : ISODate("2016-10-08T18:10:59.899Z")}},
{"date" : {$lte : ISODate("2018-10-08T18:10:59.899Z")}}]}}
, 
{ "$project" : { "custInfo" : 1 ,"count" : 1 ,   "date" : 1 , 
"duration" : {"$month" : [ "date"]}}},
{ "$group" : { "_id" : 
    { "duration" : "$duration" , "custInfo" : "$custInfo"} ,"count" : { "$sum" : 1} }}

    ]}//,
    //cursor:{batchSize:1000}

 )

请帮助我哪里错了。

问候克里斯

Answer 1

我不确定为什么 $month 在这里被认为是“持续时间”，但无论如何，您从字段变量和对 $month< 的调用中删除了一个美元符号 有点偏离。这应该有效:

{ "$project" : { "custInfo" : 1 ,
             "count" : 1 ,
             "date" : 1 ,
             "duration" : {"$month" : "$date" } }}