MongoDB集合汇总了多个对象

鉴于以下收集：

{ "_id" : ObjectId("57bb00b1471bcc08e819bff3"), "BCNED3351" : { "timestamp" : 1471873201170.0, "totalOID" : { "backlog" : 1405, "inflow" : 396, "handled" : 341 }, "queues" : { "12" : { "backlog" : 5, "inflow" : 0, "handled" : 0 }, "30" : { "backlog" : 124, "inflow" : 1, "handled" : 1 }, "31" : { "backlog" : 15, "inflow" : 40, "handled" : 29 }, "33" : { "backlog" : 1, "inflow" : 12, "handled" : 12 }, "36" : { "backlog" : 285, "inflow" : 38, "handled" : 0 }, "40" : { "backlog" : 1, "inflow" : 1, "handled" : 0 }, "42" : { "backlog" : 968, "inflow" : 268, "handled" : 267 }, "44" : { "backlog" : 5, "inflow" : 35, "handled" : 32 }, "68" : { "backlog" : 1, "inflow" : 1, "handled" : 0 } } } } /* 2 */ { "_id" : ObjectId("57bb00b2471bcc08e819bff4"), "PARED3100" : { "timestamp" : 1471873202167.0, "totalOID" : { "backlog" : 28, "inflow" : 0, "handled" : 0 }, "queues" : { "30" : { "backlog" : 25, "inflow" : 0, "handled" : 0 }, "31" : { "backlog" : 2, "inflow" : 0, "handled" : 0 }, "36" : { "backlog" : 1, "inflow" : 0, "handled" : 0 } } } } 

我正在计算集合中每个对象的每个队列的所有积压，stream入和处理元素的总和。 到目前为止，这是我为没有成功的特定队列而创build的：

 var collection = db.collection('2016-08-23'); collection.aggregate([ { $group:{ queue:'30', backlog: { $sum:{$add:['$BCNED3351.queues.30.backlog','$PARED3100.queues.30.backlog']} }, inflow: { $sum:{$add:['$BCNED3351.queues.30.inflow','$PARED3100.queues.30.inflow']} }, handled: { $sum:{$add:['$BCNED3351.queues.30.handled','$PARED3100.queues.30.handled']} } } } ], function(err, result) { console.log(result); }); 

看来add函数的第二个参数没有find，得到一个未定义的错误。 考虑到队列的数量并不总是一样的，迭代所有队列元素并为集合中的所有对象创build每个子对象的总和的最好方法是什么？

通过这段代码，我可以一次执行至less一个队列：

 var collection = db.collection('2016-08-23'); collection.aggregate([ { $group:{ _id:'30', backlog: { $sum:'$BCNED3351.queues.30.backlog' }, inflow: { $sum:'$BCNED3351.queues.30.inflow' }, handled: { $sum:'$BCNED3351.queues.30.handled' } } } ], function(err, result) { console.log(result); }); 

Answer 1

如果您可以重构您的模式以遵循此devise，例如使用示例中的文档填充testing集合以使此stream体重新devise模式：

 db.test.insert([ { "items": [ { "key": "BCNED3351", "timestamp" : 1471873201170.0, "totalOID" : { "backlog" : 1405, "inflow" : 396, "handled" : 341 }, "queues" : [ { "key": 12, "backlog" : 5, "inflow" : 0, "handled" : 0 }, { "key": 30, "backlog" : 124, "inflow" : 1, "handled" : 1 }, { "key": 31, "backlog" : 15, "inflow" : 40, "handled" : 29 }, { "key": 33, "backlog" : 1, "inflow" : 12, "handled" : 12 }, { "key": 36, "backlog" : 285, "inflow" : 38, "handled" : 0 }, { "key": 40, "backlog" : 1, "inflow" : 1, "handled" : 0 }, { "key": 42, "backlog" : 968, "inflow" : 268, "handled" : 267 }, { "key": 44, "backlog" : 5, "inflow" : 35, "handled" : 32 }, { "key": 68, "backlog" : 1, "inflow" : 1, "handled" : 0 } ] } ] }, { "items": [ { "key": "PARED3100", "timestamp" : 1471873202167.0, "totalOID" : { "backlog" : 28, "inflow" : 0, "handled" : 0 }, "queues" : [ { "key": 30, "backlog" : 25, "inflow" : 0, "handled" : 0 }, { "key": 31, "backlog" : 2, "inflow" : 0, "handled" : 0 }, { "key": 36, "backlog" : 1, "inflow" : 0, "handled" : 0 } ] } ] } ]) 

您可以运行以下聚合pipe道：

 db.test.aggregate([ { "$unwind": "$items" }, { "$unwind": "$items.queues" }, { "$group": { "_id": { "item": "$items.key", "queue": "$items.queues.key" }, "backlog": { "$sum": "$items.queues.backlog" }, "inflow": { "$sum": "$items.queues.inflow" }, "handled": { "$sum": "items.queues.handled" } } } ]) 

并得到结果：

 /* 1 */ { "_id" : { "item" : "BCNED3351", "queue" : 12 }, "backlog" : 5, "inflow" : 0, "handled" : 0 } /* 2 */ { "_id" : { "item" : "BCNED3351", "queue" : 30 }, "backlog" : 124, "inflow" : 1, "handled" : 0 } /* 3 */ { "_id" : { "item" : "BCNED3351", "queue" : 31 }, "backlog" : 15, "inflow" : 40, "handled" : 0 } /* 4 */ { "_id" : { "item" : "BCNED3351", "queue" : 33 }, "backlog" : 1, "inflow" : 12, "handled" : 0 } /* 5 */ { "_id" : { "item" : "BCNED3351", "queue" : 36 }, "backlog" : 285, "inflow" : 38, "handled" : 0 } /* 6 */ { "_id" : { "item" : "BCNED3351", "queue" : 40 }, "backlog" : 1, "inflow" : 1, "handled" : 0 } /* 7 */ { "_id" : { "item" : "BCNED3351", "queue" : 42 }, "backlog" : 968, "inflow" : 268, "handled" : 0 } /* 8 */ { "_id" : { "item" : "BCNED3351", "queue" : 44 }, "backlog" : 5, "inflow" : 35, "handled" : 0 } /* 9 */ { "_id" : { "item" : "BCNED3351", "queue" : 68 }, "backlog" : 1, "inflow" : 1, "handled" : 0 } /* 10 */ { "_id" : { "item" : "PARED3100", "queue" : 36 }, "backlog" : 1, "inflow" : 0, "handled" : 0 } /* 11 */ { "_id" : { "item" : "PARED3100", "queue" : 31 }, "backlog" : 2, "inflow" : 0, "handled" : 0 } /* 12 */ { "_id" : { "item" : "PARED3100", "queue" : 30 }, "backlog" : 25, "inflow" : 0, "handled" : 0 }