Mongodb聚合从文档内部检索文档

本文介绍了Mongodb聚合从文档内部检索文档的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我对MongoDB的聚合有疑问。

I have problems with MongoDB's aggregation.

在我的作业文档中，它具有creatorParent（单个值）和Children（由mongodb对象ID组成的数组）。在用户文档中，用户具有带有子级详细信息的子级数组。

In my "Job" document, it has creatorParent(single value) and Children(array of mongodb object id). In the "User" document, user has children array with child details.

当用户请求检索此文档时，如果数组包含child的ID，我希望汇总子级详细信息。

When user request for retrieving this document I want aggregate child details, if array contains id of child.

我在一些帮助下编写了一个汇总，它适用于creatorParent，但无论我如何尝试，都不适用于儿童。

I wrote an aggregation with some help, It worked for creatorParent but whatever I've tried, it didn't worked for children.

db.getCollection('Jobs').aggregate([ { $unwind: { path : "$children" } }, { $lookup: { "from" : "Users", "localField" : "creatorparent", "foreignField" : "_id", "as" : "creatorparent" } }, { $lookup: { "from" : "Users", "localField" : "children", "foreignField" : "children", "as" : "children" } } ])

用户文档：

{ "_id" : ObjectId("58daf84877733645eaa9b44f"), "email" : "meto93@gmail", "password" : "vpGl+Fjnef616cRgNbCkwaFDpSI=", "passwordsalt" : "99397F4A9D3A499D96694547667E74595CE994D2E83345D6953EF866303E8B65", "children" : [ { "_id" : ObjectId("58daf84977733645eaa9b450"), "name" : "Mert", "age" : 5, "additionalinformation" : "ilk cocuk", "creationtime" : ISODate("2017-03-28T23:56:56.952Z"), "userid" : ObjectId("58daf84877733645eaa9b44f"), "gender" : null }, { "_id" : ObjectId("58daf84977733645eaa9b451"), "name" : "Sencer", "age" : 7, "additionalinformation" : "ikinci cocuk", "creationtime" : ISODate("2017-03-28T23:56:56.952Z"), "userid" : ObjectId("58daf84877733645eaa9b44f"), "gender" : null } ] }

工作

{ "_id" : ObjectId("58db0a2d77733645eaa9b453"), "creationtime" : ISODate("2017-03-29T01:13:17.509Z"), "startingtime" : ISODate("2017-04-03T13:00:00.000Z"), "endingtime" : ISODate("2017-04-03T17:00:00.000Z"), "children" : [ ObjectId("58daf84977733645eaa9b450"), ObjectId("58daf84977733645eaa9b451") ], "creatorparent" : ObjectId("58daf84877733645eaa9b44f"), "applicants" : [] }

推荐答案

尝试一下：

db.jobs.aggregate( [ { $unwind: { path : "$children", } }, { $lookup: { "from" : "users", "localField" : "creatorparent", "foreignField" : "_id", "as" : "creatorparent" } }, { $lookup: { "from" : "users", "localField" : "children", "foreignField" : "children._id", "as" : "children" } }, { $addFields: { children : {$arrayElemAt : ["$children",0]} } }, { $addFields: { "children":"$children.children" } }, { $unwind: { path : "$children", } }, { $group: { "_id": "$_id", "name": { "$first": "$name" }, "jobstatus" : { "$first": "$jobstatus" }, "hourlyrate" : { "$first": "$hourlyrate" }, "creatorparent" : { "$first" : "$creatorparent" }, "children": { "$addToSet": "$children" } } }, ] );