我在mongoDB中有文档，例如:{"_id":"myId","firstName":"myFirstName","lastName":"myLastName","email":"my@email.com","age":88,"city":"myCity","country":"myCountry"}然后，我在管道中通过_id进行lookup、unwind和group。当我需要所有字段时，有什么方法可以不列出所有字段吗？{$group:{"_id":"$_id","someItemsFromLookup":{"$push":"$someItemsFromLookup"}"firstNa
考虑将这些对象放入db.invoices{"customer":"john","price":4,"weekday":"WED"}{"customer":"john","price":8,"weekday":"SUN"}{"customer":"john","price":6,"weekday":"SAT"}{"customer":"john","price":5,"weekday":"SUN"}{"customer":"bob","price":10,"weekday":"SAT"}{"customer":"bob","price":15,"weekday":"MON"}如何查询每个
我正在努力了解Mongo的整个聚合框架。我在这里有点新手。Ihavethefollowingdocuments:{"col1":"camera","fps":1,"lat":3},{"col1":"camera","fps":3,"lat":2}{"col1":"recorders","fps":9,"lat":7}{"col1":"cell","fps":8,"lat":1}{"col1":"cell","fps":4,"lat":3}如何设置返回结果:{"col1":"camera","fps":4,"lat":5},{"col1":"recorders","fps":9,"lat
我有以下间隔为15分钟的数据。[{"_id":ObjectId("5500a5e6f37a84d0509526ba"),"runtimeMilliSeconds":NumberLong("1426105802063"),"cpuMemoryStats":{"currentCpuUtilization":71.72000122070312,"currentMemoryUtilization":77.4000015258789}}{"_id":ObjectId("5500a96af37a84d0509526f8"),"runtimeMilliSeconds":NumberLong("142
使用PyMongo，一键分组似乎没问题:results=collection.group(key={"scan_status":0},condition={'date':{'$gte':startdate}},initial={"count":0},reduce=reducer)结果:{u'count':215339.0,u'scan_status':u'PENDING'}{u'count':617263.0,u'scan_status':u'DONE'}但是当我尝试按多个键进行分组时出现异常:results=collection.group(key={"scan_status":0,
在我的申请中我有以下文件{"timestamp":ISODate("2015-09-17T21:14:35.0Z"),"sensor":"gas-in","value":2.5,},{"timestamp":ISODate("2015-09-17T21:14:35.0Z"),"sensor":"gas-out","value":2.0,},{"timestamp":ISODate("2015-09-17T21:20:35.0Z"),"sensor":"gas-in","value":6.3,},{"timestamp":ISODate("2015-09-17T21:20:35.0Z")
我正在尝试使用mongotemplate创建聚合查询，其中按日期(即2016-03-01)而不是日期时间(即2016-03-0116:40:12)进行分组。dateToString操作存在于mongodb文档中，它可用于使用格式从日期时间中提取日期:https://docs.mongodb.org/manual/reference/operator/aggregation/dateToString/但我得到它与mongotemplate一起工作-我得到一个NullPointerException。(我的数据库版本是3.2)ListaggregationOperations=newArr
需要MongoDB查询/聚合:如果我有一个数组，我如何根据数组中的不同值对文档进行分组？示例:如果我有这些对象:>db.respondents.insert({person:1,responses:[{question:'Howoldareyou?',response:'18-40yrs'},{question:'Whatisthebrandofyourcar?',response:'Fiat'}]})>db.respondents.insert({person:2,responses:[{question:'Howoldareyou?',response:'18-40yrs'},{q
我有这样的数据，我想做的是通过按性别对员工进行分组来统计员工。{_id:ObjectId("57fd6b064a8d7733079d1bb9"),name:"Alex",age:23,position:"Manager",employees:[{_id:ObjectId("58056e62281b7a73dfdb6887"),employee_id:ObjectId("57df832364efef57c3540610"),name:"Bob",age:20,gender:"Male",position:"Distributor"},{_id:ObjectId("58049fe7bc82
我正在尝试将我的MongoDB文档中的2个对象分组为一个对象，并合并键。我拥有的是:{"_id":ObjectId("..."),"object_a":{"keyA":1,"keyB":"valueB"}"object_b":{"keyC":2}}我尝试得到的是:{"_id":ObjectId("..."),"object_a":{"keyA":1,"keyB":"valueB","keyC":2}}我可以断言没有key冲突我事先不知道键名我尝试使用$addFields运算符，但这会将object_b嵌套在object_a中，而不是合并键。{"$addFields":{"object_
