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
}
}
}
}
我正在尝试计算集合中每个对象的每个队列的所有积压，流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提出的：
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);
});
似乎找不到add函数的第二个参数，得到一个未定义的错误。迭代所有队列元素并为集合中的所有对象计算每个子对象的总和的最佳方法是什么，同时考虑到队列的数量并不总是相同？
使用此代码，我一次至少可以执行一个队列：
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);
});
答案 0 :(得分：2)
如果您可以重构架构以遵循此设计，例如使用示例中的文档填充测试集合以使此流体重新设计架构：
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
}
]
}
]
}
])
然后您可以运行以下聚合管道：
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
}