mongodb-query

问题 What's the syntax for doing a $lookup on a field that is an array of ObjectIds rather than just a single ObjectId? Example Order Document: { _id: ObjectId("..."), products: [ ObjectId("..<Car ObjectId>.."), ObjectId("..<Bike ObjectId>..") ] } Not Working Query: db.orders.aggregate([ { $lookup: { from: "products", localField: "products", foreignField: "_id", as: "productObjects" } } ]) Desired Result { _id: ObjectId("..."), products: [ ObjectId("..<Car ObjectId>.."), ObjectId("..<Bike ObjectId

问题 The collection has one document: { "_id" : ObjectId("54b513933aca242d9915a787"), "carriers" : [ { "carrier" : ObjectId("54b54d223aca242d9915a788"), "carryingInterval" : { "from" : ISODate("2013-12-31T23:00:00.000Z"), "to" : null } } ] } I would like to make a criteria, that is looking for a certain carrier and range. The carryingInterval 's from and to fields could be a Date object or null . The null value means +/- infinity. My criteria is: { carriers: { $elemMatch: { carrier: ObjectId(

问题 I'm trying to filter documents based on their price range, i have the following document structure example { "name": "test 1", "priceObject" : [ { "price" : { "value" : 1000 } }, { "price" : { "value" : 500 } }, { "price" : { "value" : 333 } } ] } i use aggregate to match documents that have at least one price that must be greater than 500 and less than 1000 { "$match": { "priceObject.price.value": { "$gt": 500, "$lt": 1000 } } } it return "test 1" document, although it should not, because

问题 I'm trying to filter documents based on their price range, i have the following document structure example { "name": "test 1", "priceObject" : [ { "price" : { "value" : 1000 } }, { "price" : { "value" : 500 } }, { "price" : { "value" : 333 } } ] } i use aggregate to match documents that have at least one price that must be greater than 500 and less than 1000 { "$match": { "priceObject.price.value": { "$gt": 500, "$lt": 1000 } } } it return "test 1" document, although it should not, because

问题 I have couple of documens in mongodb as follow: { "_id" : ObjectId("54901212f315dce7077204af"), "Date" : ISODate("2014-10-20T04:00:00.000Z"), "Type" : "Twitter", "Entities" : [ { "ID" : 4, "Name" : "test1", "Sentiment" : { "Value" : 20, "Neutral" : 1 } }, { "ID" : 5, "Name" : "test5", "Sentiment" : { "Value" : 10, "Neutral" : 1 } } ] } Now I want to update the document that has Entities.ID=4 by adding (Sentiment.Value+4)/2 for example in the above example after update we have 12. I wrote the

问题 I have couple of documens in mongodb as follow: { "_id" : ObjectId("54901212f315dce7077204af"), "Date" : ISODate("2014-10-20T04:00:00.000Z"), "Type" : "Twitter", "Entities" : [ { "ID" : 4, "Name" : "test1", "Sentiment" : { "Value" : 20, "Neutral" : 1 } }, { "ID" : 5, "Name" : "test5", "Sentiment" : { "Value" : 10, "Neutral" : 1 } } ] } Now I want to update the document that has Entities.ID=4 by adding (Sentiment.Value+4)/2 for example in the above example after update we have 12. I wrote the

问题 In our MongoDB document, we have two fields, organisationId and employeeId . I want to show all the elements in a collection that have either of them matching the query parameters, so a basic OR. One condition for Sorting is that I require is that the documents that have both the fields matching the query parameters should occur first, and then the documents matching organisationName parameter, next. The idea is to show the data for the employee (i.e., you) first and then that of your

问题 My basic structure is I have User object with a session object that contains a subjectId and an hourly price. User{ defaultHourly: Number, subjects{ [ id: String, hourly: Number ] } } I use elemMatch like this: query.elemMatch("subjects", { "id": { $in: subjects }, "$or": [ { "hourly": { $eq: null } }, // this is my issue { "$and": [ { "hourly": { $ne: null } }, { "hourly": { $gte: price.low, $lte: price.high } } ] } ] }); the first part of elemMatch makes sure that the subjectId I want is in

问题 is there a way to make a query such that if certain field exists it will apply WHERE like condition on that field and if it pass will add that document to the result. If such field doesn't exist, it will immediately add that document to the result? 回答1: How about something like this: db.stackoverflow.find({ $or: [ { howmuch: { $exists:false } }, { howmuch:5 } ]}) In the stackoverflow collection, this will find all documents that do not have the howmuch field plus all documents that do have

问题 is there a way to make a query such that if certain field exists it will apply WHERE like condition on that field and if it pass will add that document to the result. If such field doesn't exist, it will immediately add that document to the result? 回答1: How about something like this: db.stackoverflow.find({ $or: [ { howmuch: { $exists:false } }, { howmuch:5 } ]}) In the stackoverflow collection, this will find all documents that do not have the howmuch field plus all documents that do have