删除嵌套组中的重复项

Posted 2023-03-11

【中文标题】删除嵌套组中的重复项

【英文标题】：Remove duplicate in nested group

【发布时间】：2020-06-26 03:06:53

【问题描述】：

我必须删除与 JSON 中嵌套数组和对象中的父元素具有相同 LocateId 的元素（我正在使用 MongoDB）：

 "mainLocation": 
                  "locateId": "$numberInt": "111111",
                  "LocateName": "Indonesia",
                  "subLocation": [
                                "locateId": "$numberLong": "2222222222", *//this the refference for Child location*
                                "LocateName": "Jakarta Pusat",
                                "childLocation": [
                                                   "locateId": "$numberLong": "2222222222",
                                                   *//if the LocateId is same with Sublocation.LocateId will removed*
                                                   "LocateName": "Jakarta Pusat",
                                                 ,
                                                   "locateId": "$numberLong": "3333333333",
                                                   "LocateName": "Jakarta Barat",
                                                 ]
                                 ,
                                "locateId": "$numberLong": "1234123412",
                                "LocateName": "Bandung",
                                "childLocation": []
                                 ]
                 

而我的预期是：

 "mainLocation": 
                  "locateId": "$numberInt": "111111",
                  "LocateName": "Indonesia",
                  "subLocation": [
                                "locateId": "$numberLong": "2222222222",
                                "LocateName": "Jakarta Pusat",
                                "childLocation": [
                                                   "locateId": "$numberLong": "3333333333",
                                                   "LocateName": "Jakarta Barat",
                                                 ] *//the element with same Id has been removed*
                                 ,
                                "locateId": "$numberLong": "1234123412",
                                "LocateName": "Bandung",
                                "childLocation": []
                                 ]
                 

我尝试了简单的功能，至少可以按我预期的顺序显示

db.pages.aggregate(
    [ 
            "$group" : 
                LocatediId: "$mainLocation.LocatediId",
                subLocation : 
                        "$group" :  
                        LocatediId: "$mainLocation.subLocation.LocatediId",
                        Locatedname: "$mainLocation.subLocation.Locatedname"
                        
        
    ]);

所以我可以将结果导出到 JSON 文件。

【问题讨论】：

您的查询是什么？

您可以通过$filter 完成此操作

请添加您尝试过的一些功能。还结帐行为准则

其实我不知道.. 只是尝试从另一个代码传递.. 并替换变量.. 我还没有找到那个嵌套组.. 我尝试嵌套组但那也是错误......

【参考方案1】：

试试这个：

db.collection.aggregate([
   
      $set: 
         "mainLocation.subLocation": 
            $map: 
               input: "$mainLocation.subLocation",
               as: "subLocation",
               in: 
                  $mergeObjects: [
                     "$$subLocation",
                     
                        childLocation: 
                           $filter: 
                              input: "$$subLocation.childLocation",
                              cond:  $ne: ["$$this.locateId", "$$subLocation.locateId"] 
                           
                        
                     
                  ]
               
            
         
      
   
])

Mongo playground

【讨论】：

谢谢..我不知道它可能很复杂..它节省了很多时间和精力