Question

我的mongoDB查询存在一个问题（使用aggregate）。我很乐意得到一些线索......

在我的MongoCollection下面：
请注意，KLLS可以是a，b或c，还有3 types：processus，work和{ {1}}。

viewing

我想通过查询实现的目标：

{_id: 1, KLLS: "a", action: "A", type: "Processus", date: Date, other:"abc" }
{_id: 2, KLLS: "b", action: "B", type: "Processus", date: Date }
{_id: 3, KLLS: "a", action: "C", type: "Work"     , date: Date, other:"xyz" }
{_id: 4, KLLS: "b", action: "D", type: "Work"     , date: Date }
{_id: 5, KLLS: "a", action: "E", type: "Viewing"  , date: Date }
{_id: 6, KLLS: "b", action: "F", type: "Viewing"  , date: Date }
...

此时，我的（失败）查询是：

[ { 
    _id: { KLLS: "a"},
    Processus: [[action: "A", date: "Date", other: "abc"]]
    Work:      [[action: "C", date: "Date"]]
    Viewing:   [[action: "E", date: "Date"]]
  },
  { 
    _id: { KLLS: "b"},
    Processus: [[action: "B", date: "Date"]]
    Work:      [[action: "D", date: "Date", other: "xyz"]]
    Viewing:   [[action: "F", date: "Date"]]
  }
]

但是，我有一个问题：它产生db.collection('events').aggregate([ {$match: { KLLS: {$in: something} }}, {$group: { _id: { klls: "$KLLS", type: "$type" }, array: { $push: "$$ROOT" } }} ])但我没有3个名字很好的composite id ......

arrays

你知道如何解决这个问题吗？感谢。

********************编辑********************** < /强>

让我们假设同样的集合也包含：

[ { _id: { KLLS: "a", type: "Processus" }, array: [[action: "A", date: "Date", other: "abc"]] }, { _id: { KLLS: "a", type: "Work" }, array: [[action: "C", date: "Date"]] }, { _id: { KLLS: "a", type: "Viewing" }, array: [[action: "E", date: "Date"]] }, { _id: { KLLS: "b", type: "Processus" }, array: [[action: "B", date: "Date"]] }, { _id: { KLLS: "b", type: "Work" }, array: [[action: "D", date: "Date", other: "xyz"]] }, { _id: { KLLS: "b", type: "Viewing" }, array: [[action: "F", date: "Date"]] }, ... ]

（请注意，对于类型{_id: 1, KLLS: "a", action: "A", type: "Processus", date: Date } {_id: 2, KLLS: "b", action: "B", type: "Processus", date: Date } {_id: 5, KLLS: "a", action: "E", type: "Viewing" , date: Date } {_id: 6, KLLS: "b", action: "F", type: "Viewing" , date: Date } ... {_id: 3, KLLS: "a", action: "AB", type: "Work" , date: Date, key:"123" } {_id: 4, KLLS: "b", action: "XY", type: "Work" , date: Date, key: "123" } {_id: 3, KLLS: "a", action: "AB", type: "Work" , date: Date, key:"456" } {_id: 4, KLLS: "b", action: "XY", type: "Work" , date: Date, key: "456" } ...，我有另一个Work）。

感谢您的帮助，此时此刻，我得到了：

key

然而，我想要的最终结果是：

[{ _id: { KLLS: "a"}, Processus: [ everything is ok ], Viewing: [ everything is ok ], Details: [ everything is ok ], Work: [ {_id: 3, KLLS: "a", action: "AB", type: "Work", date: Date, key:"123" } {_id: 4, KLLS: "b", action: "XY", type: "Work", date: Date, key: "123" } {_id: 3, KLLS: "a", action: "AB", type: "Work", date: Date, key:"456" } {_id: 4, KLLS: "b", action: "XY", type: "Work", date: Date, key: "456" } ] ...

我尝试了（1）一种[{ _id: { KLLS: "a"}, Processus: [ everything is ok ], Viewing: [ everything is ok ], Details: [ everything is ok ], Work: [ subArrayByKey [ // key = 123 {_id: 3, KLLS: "a", action: "AB", type: "Work", date: Date, key:"123" }, {_id: 4, KLLS: "b", action: "XY", type: "Work", date: Date, key: "123" } ], subArrayByKey [ // key = 456 {_id: 3, KLLS: "a", action: "AB", type: "Work", date: Date, key:"456" }, {_id: 4, KLLS: "b", action: "XY", type: "Work", date: Date, key: "456" } ] ] ...以及（2）将标准添加到您的第一个$组中以制作nested $group（就像我在开始时尝试过的那样）。但composite id使我感到尴尬......

$eq

最后，并不奇怪，我失败了...返回查询不是空的.. 如果我可以..你有任何线索......; - ）

Answer 1

您可以将$cond运算符与$push一起使用，以便为符合条件的数组添加值。

$cond是三元运算符，在下面的示例中，当满足条件时，原始文档将添加到数组中，并且当条件不满足时，将虚拟值false添加到数组中

在最后的$project阶段，使用false运算符删除数组中的虚拟setDifference条目。

db.events.aggregate([
    {"$group": {
         "_id" : "$KLLS",
         "Processus": {
             "$push": { 
                 "$cond": [{"$eq": ["$type", "Processus"]}, "$$ROOT", false]
             }
         },
         "Work": {
             "$push": {
                 "$cond": [{"$eq": ["$type","Work"]}, "$$ROOT", false]
             }
         },
         "Viewing": {
             "$push": {
                 "$cond": [{"$eq" : ["$type","Viewing"]}, "$$ROOT", false]
             }
         },
         "Details": {"$push" : "$other"}
    }},

    {"$project": {
         "_id": 0, 
         "KLLS": "$_id",
         "Processus": {"$setDifference": ["$Processus", [false]]},
         "Work":      {"$setDifference": ["$Work",      [false]]},
         "Viewing":   {"$setDifference": ["$Viewing",   [false]]},
         "Details": 1
    }}
])

此外，要向数组中添加少量字段，您可以尝试以下内容。

db.events.aggregate([
    {"$group": {
         "_id": "$KLLS",
         "Processus": {
             "$push": { 
                 "$cond": [{"$eq": ["$type","Processus"]}, {"action": "$action","other": "$other"}, false]
             }
          },
          "Work": {
              "$push": {
                  "$cond": [{"$eq": ["$type","Work"]}, {"action": "$action","other": "$other"}, false]
              }
          },
          "Viewing":{
              "$push": {
                  "$cond": [{"$eq": ["$type","Viewing"]}, {"action": "$action","other": "$other"}, false]
              }
          },
          "Details": {"$push": "$other"}
    }},

    {"$project": { 
         "_id": 0, 
         "KLLS": "$_id",
         "Processus": {"$setDifference": ["$Processus", [false]]},
         "Work":      {"$setDifference": ["$Work",      [false]]},
         "Viewing":   {"$setDifference": ["$Viewing",   [false]]},
         "Details": 1
    }}
])

MongoDB聚合`$ group`和数组名称

1 个答案: