对嵌套对象数组的mongoDB聚合查找
对嵌套对象数组的mongoDB聚合查找
提问于 2019-09-24 22:32:18
我有一个如下所示的集合，我在执行$lookup并返回它时遇到了麻烦，因为它是以填充字段的形式返回的：
我已经对要填充的字段进行了注释，这些字段是(座席、missions.clients.client)
{
"title":"Tournée libre",
"agent":"5d811943d2a2100017667228", // needs to be populated
"missions":[
{
"_id":"5d8a075346f10d679ab4383e",
"title":"Journée 3",
"clients":[
{
"_id":"5d8a075346f10d679ab4383f",
"valid":true,
"client":"5d1bc39aa2af623b94363b33", // this needs to be populated
"visit_time":"2019-09-24T12:03:38.383Z"
},
{
"_id":"5d8a0dc446f10d679ab43888",
"valid":true,
"client":"5d8a0c8346f10d679ab43886",
"visit_time":"2019-09-24T12:34:23.210Z"
},
]
}
],
"created_at":"2019-09-24T12:08:51.928Z",
"__v":2
}结果应该是这样的：
{
"title":"Tournée libre",
"agent": {firstname: 'something', lastname: 'something else'}
"missions":[
{
"_id":"5d8a075346f10d679ab4383e",
"title":"Journée 3",
"clients":[
{
"_id":"5d8a075346f10d679ab4383f",
"valid":true,
"client": {firstname: 'something', lastname: 'something else'},
"visit_time":"2019-09-24T12:03:38.383Z"
},
{
"_id":"5d8a0dc446f10d679ab43888",
"valid":true,
"client":{firstname: 'something', lastname: 'something else'},
"visit_time":"2019-09-24T12:34:23.210Z"
},
]
}
],
"created_at":"2019-09-24T12:08:51.928Z",
"__v":2
}回答 1
Stack Overflow用户
回答已采纳
发布于 2019-09-29 21:11:29
您可以使用下面的聚合管道。
使用$lookup填充代理，然后使用$reduce和$concatArrays收集所有客户端ids，使用$lookup获取客户端详细信息。
使用$addFields和$map来迭代任务数组，对于每个客户端，通过按客户端id和$mergeObjects进行查找来映射来自前一阶段的客户端信息，以保留其他字段。$project阶段删除额外的字段。
Mongo db 3.6及以上版本
Model.aggregate([
{"$lookup":{
"from":"agents",
"localField":"agent",
"foreignField":"_id",
"as":"agent"
}},
{"$addFields":{"agent":{"$arrayElemAt":["$agent",0]}}},
{"$addFields":{
"client_ids":{
"$reduce":{
"input":"$missions",
"initialValue":[],
"in": {"$concatArrays":["$$value","$$this.clients.client"]}
}
}
}},
{"$lookup":{
"from":"clients",
"localField":"client_ids",
"foreignField":"_id",
"as":"client_info"
}},
{"$addFields":{
"missions":{
"$map":{
"input":"$missions",
"in":{
"$mergeObjects":[
"$$this",
{"clients":{"$map":{
"input":"$$this.clients",
"in":{"$mergeObjects":[
"$$this",
{"client":{"$arrayElemAt":[
"$client_info",
{"$indexOfArray":["$client_ids","$$this._id"]}
]}}
]}
}}}
]
}
}
}
}},
{"$project":{"client_ids":0,"client_info":0}}
])Mongo db小于3.6
使用$lookup填充代理，然后使用$unwind访问客户端并查找以获取客户端详细信息。使用$group回放以带回填充了值的原始结构。
Model.aggregate([
{"$lookup":{
"from":"agents",
"localField":"agent",
"foreignField":"_id",
"as":"agent"
}},
{"$addFields":{"agent":{"$arrayElemAt":["$agent",0]}}},
{"$unwind":"$missions"},
{"$unwind":"$missions.clients"},
{"$lookup":{
"from":"clients",
"localField":"missions.clients.client",
"foreignField":"_id",
"as":"missions.clients.client"
}},
{"$addFields":{"missions.clients.client":{"$arrayElemAt":["$missions.clients.client",0]}}},
{"$group":{
"_id":{"_id":"$_id","mission_id":"$missions._id"},
"agent":{"$first":"$agent"},
"title":{"$first":"$missions.title"},
"clients":{"$push":"$missions.clients"}
}},
{"$group":{
"_id":"$_id._id",
"agent":{"$first":"$agent"},
"missions":{
"$push":{
"_id":"$_id.mission_id",
"title":"$title",
"clients":"$clients"
}
}
}}
])页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/58082664
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