pipeline := []bson.M{ bson.M{"$match": bson.M{"id": uid}}, bson.M{"$project": bson.M{"last_msg": 1, "_id": 0}}, bson.M{"$unwind": "$last_msg"}, bson.M{"$sort": bson.M{"last_msg": -1}}, bson.M{"$skip": 2}, bson.M{"$limit": 2}, } userModel := MongoDb.C("user") pipe := userModel.Pipe(pipeline) var data []interface{} err := pipe.All(&data) fmt.Println(data) fmt.Println(len(data))
等效于
db.getCollection("user").aggregate([ {$match: {"id":"1"}}, {$project:{"last_msg":1, "_id":0}}, {$unwind: "$last_msg"}, {$sort: {"last_msg.date":-1}}, {$skip:2}, {$limit:2} ]);
mongodb表结构:
其中一条数据:
{ "_id": ObjectId("5d2b24c16197934ef6db77ba"), "id": "1", "account": "你的女神", "passwd": "5d78eb174d633345054faf7d56a612ed", "friends": [ { "uid": "2" }, { "uid": "3" } ], "last_msg": [ { "date": "1234567890", "from_id": "2", "msg": "在么" }, { "date": "1234567895", "from_id": "3", "msg": "女神" }, { "date": "1234567898", "from_id": "4", "msg": "求你了,理理我好么" }, { "date": "1234567999", "from_id": "5", "msg": "你是不是在和别人..." } ] }
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