Mongodb每两小时汇总一次
Mongodb每两小时汇总一次
提问于 2016-08-03 04:24:30
我对以下表单有一个聚合查询
db.mycollection.aggregate([
{
"$match":
{
"Time": { $gte: ISODate("2016-01-30T00:00:00.000+0000") }
}
},
{
"$group":
{
"_id":
{
"day": { "$dayOfYear": "$Time" },
"hour": { "$hour": "$Time" }
},
"Dishes": { "$addToSet": "$Dish" }
}
},
{
"$group":
{
"_id": "$_id.hour",
"Food":
{
"$push":
{
"Day": "$_id.day",
"NumberOfDishes": { "$size":"$Dishes" }
}
}
}
},
{
"$project":
{
"Hour": "$_id",
"Food": "$Food",
"_id" : 0
}
},
{
"$sort": { "Hour": 1 }
}
]);我不想像上面那样在一个小时的持续时间里这样做，比如0-1,1-2,2-3,3-4,4-5，.，23-24，我想在两个小时的时间内做到这一点。例如0-2,2-4,4-6，.，22-24。有办法吗？
回答 1
Stack Overflow用户
发布于 2016-08-03 07:23:22
比方说，H=floor(hour/2)，其中hour是从文档日期开始的实际时间。然后，您可以通过在此日期应用$floor和$divide运算符来获得$floor。
"H": { $floor: { $divide: [ { "$hour": "$Time" }, 2 ] } }这里H对应于对小时(Hours=[0,2) => H=0，Hours=[2,4) => H=1，Hours=[22,24) => H=11等)你可以把它传递到$group阶段
$group: { "_id": { "day": { $dayOfYear: "$Time" }, "H": "$H" } }然后，您可以为特定的H输出对小时。
"Hours": [ { $multiply: [ "$H", 2 ] }, { $sum: [ { $multiply: [ "$H", 2 ] }, 2 ] } ]给定的文件收集
{ "Time" : ISODate("2016-01-30T01:00:00Z"), "Dish" : "dish1" }
{ "Time" : ISODate("2016-01-30T02:00:00Z"), "Dish" : "dish2" }
{ "Time" : ISODate("2016-01-30T03:00:00Z"), "Dish" : "dish3" }
{ "Time" : ISODate("2016-01-30T04:00:00Z"), "Dish" : "dish4" }
{ "Time" : ISODate("2016-01-30T05:00:00Z"), "Dish" : "dish5" }
{ "Time" : ISODate("2016-01-30T06:00:00Z"), "Dish" : "dish6" }
{ "Time" : ISODate("2016-01-30T07:00:00Z"), "Dish" : "dish7" }
{ "Time" : ISODate("2016-01-30T08:00:00Z"), "Dish" : "dish8" }
{ "Time" : ISODate("2016-01-30T09:00:00Z"), "Dish" : "dish9" }并使用其上的下一个聚合
db.mycollection.aggregate([
{
"$match":
{
"Time": { $gte: ISODate("2016-01-30T00:00:00.000+0000") }
}
},
{
"$project":
{
"Dish": 1,
"Time": 1,
"H": { $floor: { $divide: [ { $hour: "$Time" }, 2 ] } }
}
},
{
"$group":
{
"_id":
{
"day": { $dayOfYear: "$Time" },
"H": "$H"
},
"Dishes": { $addToSet: "$Dish" }
}
},
{
"$group":
{
"_id": "$_id.H",
"Food":
{
"$push":
{
"Day": "$_id.day",
"NumberOfDishes": { $size: "$Dishes" }
}
}
}
},
{
"$sort": { "_id": 1 }
},
{
"$project":
{
"Hours": [ { $multiply: [ "$_id", 2 ] }, { $sum: [ { $multiply: [ "$_id", 2 ] }, 2 ] } ],
"Food": "$Food",
"_id": 0
}
}
]);提供结果
{ "Food" : [ { "Day" : 30, "NumberOfDishes" : 1 } ], "Hours" : [ 0, 2 ] }
{ "Food" : [ { "Day" : 30, "NumberOfDishes" : 2 } ], "Hours" : [ 2, 4 ] }
{ "Food" : [ { "Day" : 30, "NumberOfDishes" : 2 } ], "Hours" : [ 4, 6 ] }
{ "Food" : [ { "Day" : 30, "NumberOfDishes" : 2 } ], "Hours" : [ 6, 8 ] }
{ "Food" : [ { "Day" : 30, "NumberOfDishes" : 2 } ], "Hours" : [ 8, 10 ] }页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/38734389
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