mongodb-query

问题 I have data in worksheets collection like below: /* 1 */ { "_id" : ObjectId("5c21d780f82aa31334ab6506"), "isBilling" : true, "hours" : 6, "userId" : ObjectId("5c1f38a1d7537d1444738493"), } /* 2 */ { "_id" : ObjectId("5c21d780f82aa31334ab6507"), "isBilling" : true, "hours" : 4, "userId" : ObjectId("5c1f38a1d7537d1444738493"), } /* 3 */ { "_id" : ObjectId("5c21e10fae07cc1204a5b647"), "isBilling" : false, "hours" : 8, "userId" : ObjectId("5c1f388fd7537d1444738492"), } I have to create a

问题 seasons.json { "_id" : "unique_1", "spring" : [{ "fruit" : "mango", "person_id" : [101.0, 102.0, 103.0, 104.0] }, { "fruit" : "banana", "person_id" : [151.0, 152.0, 153.0, 154.0] }], "summer" : [{ "fruit" : "mango", "person_id" : [201.0, 202.0, 203.0, 204.0] }, { "fruit" : "banana", "person_id" : [251.0, 252.0, 253.0, 254.0] }], "fall" : [{ "fruit" : "mango", "person_id" : [301.0, 302.0, 303.0, 304.0] }, { "fruit" : "banana", "person_id" : [351.0, 352.0, 353.0, 354.0] }], "winter" : [{ "fruit

问题 I want to delete an embedded object from an array, using this query. It works fine, but the result is always 1. No matter if an array element was pulled or not. This makes it hard to respond to the request in a proper way. db.clients.update({_id: someId}, {$pull: {someArray: {id: req.params.id}}}, function(err, result) { if (err) return next(err); res.json(result); }); Q) Is there a way to make this query return for example null or zero when an element is not pulled? 回答1: While there have

问题 This question is a follow up to a previous question for which I have accepted an answer already. I have an aggregate query that returns the results of a deeply nested array of subdocuments based on a date range. The query returns the correct results within the specified date range, however it also returns an empty array for the results that do not match the query. Technologies: MongoDB 3.6, Mongoose 5.5, NodeJS 12 Question 1: Is there any way to remove the results that don't match the query?

问题 Am completely new to Mongodb and C# driver. Development is being done using Monodevelop on Ubuntu 14.04 and Mongodb's version is 3.2.10 : Currently my code has a POCO as below: public class User { public String Name { get; set;} public DateTime LastModifiedAt { get; set;} public DateTime LastSyncedAt { get; set;} public User () { } } Have been able to create a collection and also to add users. How do I find users, whose LastModifiedAt timestamp is greater than LastSyncedAt timestamp ? Did

问题 I have a large collection called Messages , like so: { user: 94fg844f, event: null, group: null, name: "Jake", text: "Hello world" }, { user: fje93jrg4, event: null, group: null, name: "Bob" text: "Testing" }, { user: fje93jrg4, event: null, group: null, name: "Bob" text: "Text here" }, { user: null, event: d0j3n9fn3, group: null, name: "My Event" text: "Testing 2" }, { user: null, event: d0j3n9fn3, group: null, name: "My Event" text: "Another text" } I need to get the first occurrence of the

问题 I'm trying to group by "group_name" and select fields "group_name" and "group_id" with php driver using aggregation framework: Array ( [$project] => Array ( [group_name] => 1 [group_id] => 1 ) [$group] => Array ( [_id] => $group_name [total_sum] => Array ( [$sum] => 1 ) ) ) I'm getting this: [errmsg] => exception: A pipeline stage specification object must contain exactly one field. However, when I'm using only $project or $group operator it works just fine. 回答1: The issue is your grouping

问题 I have following offers collection Here readBy contains the _id of the users... Now I want to count the number of unRead offers for the userId = "5add82620d7f5b38240c63d4" { "_id" : ObjectId("5aeaab5ed6a9c97d0209260a"), "expiresIn" : ISODate("2018-05-30T18:30:00.000Z"), "name" : "Trip ", "readBy" : [ ObjectId("5add82620d7f5b38240c63d4"), ObjectId("5add82620d7f5b38240c63c6") ], "__v" : 0 } { "_id" : ObjectId("5aeaab7dd6a9c97d0209260b"), "expiresIn" : ISODate("2018-05-29T18:30:00.000Z"), "name"

问题 Consider the following document in the collection named 'CityAssociation' { "_id" : "MY_ID", "ThisCityID" : "001", "CityIDs" : [{ "CityID" : "001", "CityName" : "Bangalore" }, { "CityID" : "002", "CityName" : "Mysore" }], "CityUserDetails": { "User" : "ABCD" } } Now I have User value i.e. in above case I have value ABCD and want to find it with only city where the first level's field ThisCityID matches to the embedded array documnet's field CityID . Finally I need to project as follows (for

问题 I have a filter + group operation on a bunch of documents (books). The grouping is to return only latest versions of books that share the same book_id (name). The below code works, but it's untidy since it returns redundant information: return Book.aggregate([ { $match: generateMLabQuery(rawQuery) }, { $sort: { "published_date": -1 } }, { $group: { _id: "$book_id", books: { $first: "$$ROOT" } } } ]) I end up with an array of objects that looks like this: [{ _id: "aedrtgt6854earg864", books: {