$ filter在mongodb中最多2个嵌套级别

我期望的是: [{"utis" : [{"_id" : NumberInt("893910"),"nome" : "UTI1","leitos" : [{"_id" : NumberInt("128938120"),"_paciente" : "Oliver"},{"_id" : NumberLong("12803918239"),"_paciente" : "Priscilla"}]}],"nome" : "Dorio Silva"}] 但是那绝不是结果，我可以按要求发布结果，但我认为可能不需要.查询结果的正确方法是什么?我建立数据库的方式有什么问题吗?可以做得更好吗?解决方案您需要 $unwind 第一个数组，那么您可以轻松地应用 $filter 在嵌套数组上db.collection.aggregate([ { "$unwind": "$Hospitais" }, { "$match": { "Hospitais.nome": "Dorio Silva" } }, { "$project": { "Hospitais": { "$filter": { "input": "$Hospitais.utis", "as": "uti", "cond": { "$eq": ["$$uti.nome", "UTI1"] } } } }}])或者您也可以尝试db.collection.aggregate([ { "$match": { "Hospitais.nome": "Dorio Silva" } }, { "$project": { "Hospitais": { "$filter": { "input": { "$map": { "input": "$Hospitais", "as": "hospital", "in": { "nome": "$$hospital.nome", "utis": { "$filter": { "input": "$$hospital.utis", "as": "uti", "cond": { "$eq": ["$$uti.nome", "UTI1"] } } } } } }, "as": "hospital", "cond": { "$eq": ["$$hospital.nome", "Dorio Silva"] } } } }}])两者都会给出相似的输出[ { "Hospitais": [ { "_id": 893910, "leitos": [ { "_id": 1.2893812e+08, "_paciente": "Oliver" }, { "_id": 1.2803918239e+10, "_paciente": "Priscilla" } ], "nome": "UTI1" } ] }]i have a database structured like this:{ "Hospitais": [ { "utis": [ { "_id": 893910, "nome": "UTI1", "leitos": [ { "_id": 128938120, "_paciente": "Oliver" }, { "_id": 12803918239, "_paciente": "Priscilla" } ] }, { "_id": 38471839, "nome": "UTI2", "leitos": [ { "_id": 48102938109, "_paciente": "Serveró" }, { "_id": 501293890, "_paciente": "Thales" } ] }, { "_id": 58109238190, "nome": "UTI3", "leitos": [ { "_id": 93801293890, "_paciente": "Lucia" }, { "_id": 571029390, "_paciente": "Amanda" } ] } ], "nome": "Dorio Silva" }, { "utis": [ { "_id": 410923810, "nome": "UTI1", "leitos": [ { "_id": 48102938190, "_paciente": "Neymar" }, { "_id": 48102938190, "_paciente": "Thiago" } ] }, { "_id": 41092381029, "nome": "UTI2", "leitos": [ { "_id": 10293182309, "_paciente": "Brazza" }, { "_id": 38190238, "_paciente": "Pelé" } ] }, { "_id": 83102938109, "nome": "UTI3", "leitos": [ { "_id": 810923810, "_paciente": "Aparecida" }, { "_id": 20938904209, "_paciente": "Pimentinha" } ] } ], "nome": "Apart Hospital" }]}I need to return just the array of Hospitais that have a match with a input of 'Hospitais.nome' and also, there is a array inside each array of Hospitais called 'utis', i want to filter it too together, there is a "Expected Result" bellow.I have tried this from many different ways and the most recent one i've been trying is this code :db.collection.aggregate([ { "$match": { "Hospitais.nome": 'Dorio Silva'} }, { "$project": { _id: 0, Hospitais: { $filter: { input: "$Hospitais", as: "hospital", cond: { $and: [{$eq: ["$$hospital.nome", 'Dorio Silva']},{ $eq: ["$$hospital.utis.nome",'UTI1']}]} } } } }]);As far as i understood about aggregation filter, it should only show the objects of the array Hospitais where Hospital.nome is 'Dorio Silva' and the object of Hospital.utis where Hospital.utis.nome is 'UTI1'What i was expecting:[{"utis" : [{"_id" : NumberInt("893910"),"nome" : "UTI1","leitos" : [{"_id" : NumberInt("128938120"),"_paciente" : "Oliver"},{"_id" : NumberLong("12803918239"),"_paciente" : "Priscilla"}]}],"nome" : "Dorio Silva"}]But thats never the result, i can post the results if asked, but i don't think it may be needed.What is the right way to query my result? Is there anything wrong with the way i'm building my database? It could be done better? 解决方案 You need to $unwind the first array then you can easily apply $filter on the nested arraydb.collection.aggregate([ { "$unwind": "$Hospitais" }, { "$match": { "Hospitais.nome": "Dorio Silva" } }, { "$project": { "Hospitais": { "$filter": { "input": "$Hospitais.utis", "as": "uti", "cond": { "$eq": ["$$uti.nome", "UTI1"] } } } }}])Or you can try this as welldb.collection.aggregate([ { "$match": { "Hospitais.nome": "Dorio Silva" } }, { "$project": { "Hospitais": { "$filter": { "input": { "$map": { "input": "$Hospitais", "as": "hospital", "in": { "nome": "$$hospital.nome", "utis": { "$filter": { "input": "$$hospital.utis", "as": "uti", "cond": { "$eq": ["$$uti.nome", "UTI1"] } } } } } }, "as": "hospital", "cond": { "$eq": ["$$hospital.nome", "Dorio Silva"] } } } }}])Both will give the similar output[ { "Hospitais": [ { "_id": 893910, "leitos": [ { "_id": 1.2893812e+08, "_paciente": "Oliver" }, { "_id": 1.2803918239e+10, "_paciente": "Priscilla" } ], "nome": "UTI1" } ] }] 这篇关于$ filter在mongodb中最多2个嵌套级别的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！