aggregation-framework

问题 My mongo database contains a collection 'Shops' and the data is like below: { "_id" : ObjectId("XXXX1b83d2b227XXXX"), "ShopId" : 435, "products" : [ { "productId" : "1234", "productName" : "non veg", "productCategory" : "meals", "mrp" : "38", }, { "productId" : "5234", "productName" : "non veg", "productCategory" : "meals", "mrp" : "38", }, { "productId" : "6234", "productName" : "apple", "productCategory" : "juice", "mrp" : "38", }, { "productId" : "7234", "productName" : "non veg",

问题 I have documents that have a few fields and in particular the have a field called attrs that is an array. I am using the aggregation pipeline. In my query I am interested in the attrs (attributes) field if there are any elements in it. Otherwise I still want to get the result. In this case I am after the field type of the document. The problem is that if a document does not contain any element in the attrs field it will be filtered away and I won't get its _id.type field, which is what I

问题 I have these documents: { "_id" : ObjectId("52abac78f8b13c1e6d05aeed"), "score" : 125494, "updated" : ISODate("2013-12-14T00:55:20.339Z"), "url" : "http://pictwittrer.com/1crfS1t" } { "_id" : ObjectId("52abac86f8b13c1e6d05af0f"), "score" : 123166, "updated" : ISODate("2013-12-14T00:55:34.354Z"), "url" : "http://bit.ly/JghJ1N" } Now, i would like to get all documents sorted by this dynamic ranking: ranking = score / (NOW - updated).abs ranking is a float value where: - score is the value of

问题 I want to sum a field by using pipeline := []bson.M{ bson.M{"$group": bson.M{ "_id": "", "count": bson.M{ "$sum": 1}}} } ctx, _ := context.WithTimeout(context.Background(), 5*time.Second) result, err := collection.Aggregate(ctx, pipeline) but it always return "Current": null Any solution? 回答1: First, Collection.Aggregate() returns a mongo.Cursor, not the "direct" result. You have to iterate over the cursor to get the result documents (e.g. with Cursor.Next() and Cursor.Decode()), or use

问题 I have a problem in mongodb. I want to create aggregation witch result will be like this: A 10 B 2 C 4 D 9 E 3 ... I have a column words in my table and I want to group my records according to first character of column words . I find resolve for sql but not for mongo. I will be very grateful for your help 回答1: You don't show what the docs in your collection look like, but you can use the aggregate collection method to do this: // Group by the first letter of the 'words' field of each doc in

问题 I'm trying to dynamically sticky sort a collection of records with the value that is sticky being different with each query. Let me give an example. Here are some example docs: {first_name: 'Joe', last_name: 'Blow', offices: ['GA', 'FL']} {first_name: 'Joe', last_name: 'Johnson', offices: ['FL']} {first_name: 'Daniel', last_name: 'Aiken', offices: ['TN', 'SC']} {first_name: 'Daniel', last_name: 'Madison', offices: ['SC', 'GA']} ... a bunch more names ... Now suppose I want to display the

问题 I have a situation where I have got one result from aggregation where I am getting data in this format. { "_id" : ObjectId("5a42432d69cbfed9a410e8ad"), "bacId" : "BAC0023444", "cardId" : "2", "defaultCardOrder" : "2", "alias" : "Finance", "label" : "Finance", "for" : "", "cardTooltip" : { "enable" : true, "text" : "" }, "dataBlocks" : [ { "defaultBlockOrder" : "1", "blockId" : "1", "data" : "0" }, { "defaultBlockOrder" : "2", "blockId" : "2", "data" : "0" }, { "defaultBlockOrder" : "3",

问题 I would like to know if this is even possible. Actually my query is : a near query on Users table + a forEach loop of find queries on UserSports table where user._id = userId of UserSports (it's like a join done in a foreach) : //geonear query db.users.find({ geopoint_mongo: {$near: {$geometry: {type: "Point", coordinates: [userGeopoint.lng, userGeopoint.lat]}, $maxDistance: maxDistance * 1000 } } }, {_id: 1, geopoint: 1, url_avatar: 1, bool_coach: 1, bool_ambassador: 1, gender: 1, bool

问题 I grouped results by mvid and the counted number of occurrences in each group. db.some_details.aggregate([ {$group: {_id: "$mvid", count: {$sum: 1}}} ]) Now, I would like to select group with max count. Here is my naive guess: db.some_details.aggregate([ {$group: {_id: "$mvid", count: {$sum: 1}}}, {$max: "count"} ]) It, obviously, generates an error. I need to use max with group, but I don't have anything to group on. 回答1: What also would work is sorting the result and then using only the

问题 Here is my mongo collection 'sales': {"title":"Foo", "hash": 17, "num_sold": 49, "place": "ABC"} {"title":"Bar", "hash": 18, "num_sold": 55, "place": "CDF"} {"title":"Baz", "hash": 17, "num_sold": 55, "place": "JKN"} {"title":"Spam", "hash": 17, "num_sold": 20, "place": "ZSD"} {"title":"Eggs", "hash": 18, "num_sold": 20, "place": "ZDF"} I would like to group by hash and return document with the greatest "num_sold". So as output I would like to see: {"title":"Baz", "hash": 17, "num_sold": 55,