Is it possible to find in a nested array the max date and show its price then show the parent field like the actual price.
是否有可能在嵌套数组中找到最大日期并显示其价格,然后显示父字段,如实际价格。
The result I want it to show like this :
结果我希望它显示如下:
{
"_id" : ObjectId("5547e45c97d8b2c816c994c8"),
"actualPrice":19500,
"lastModifDate" :ISODate("2015-05-04T22:53:50.583Z"),
"price":"16000"
}
The data :
数据 :
db.adds.findOne()
{
"_id" : ObjectId("5547e45c97d8b2c816c994c8"),
"addTitle" : "Clio pack luxe",
"actualPrice" : 19500,
"fistModificationDate" : ISODate("2015-05-03T22:00:00Z"),
"addID" : "1746540",
"history" : [
{
"price" : 18000,
"modifDate" : ISODate("2015-05-04T22:01:47.272Z"),
"_id" : ObjectId("5547ec4bfeb20b0414e8e51b")
},
{
"price" : 16000,
"modifDate" : ISODate("2015-05-04T22:53:50.583Z"),
"_id" : ObjectId("5547f87e83a1dae00bc033fa")
},
{
"price" : 19000,
"modifDate" : ISODate("2015-04-04T22:53:50.583Z"),
"_id" : ObjectId("5547f87e83a1dae00bc033fe")
}
],
"__v" : 1
}
my query
db.adds.aggregate(
[
{ $match:{addID:"1746540"}},
{ $unwind:"$history"},
{ $group:{
_id:0,
lastModifDate:{$max:"$historique.modifDate"}
}
}
])
I dont know how to include other fields I used $project but I get errors thanks for helping
我不知道如何包含我使用$ project的其他字段但是我得到错误感谢帮助
1 个解决方案
#1
You could try the following aggregation pipeline which does not need to make use of the $group
operator stage as the $project
operator takes care of the fields projection:
您可以尝试以下聚合管道,它不需要使用$ group运算符阶段,因为$ project运算符负责字段投影:
db.adds.aggregate([
{
"$match": {"addID": "1746540"}
},
{
"$unwind": "$history"
},
{
"$project": {
"actualPrice": 1,
"lastModifDate": "$history.modifDate",
"price": "$history.price"
}
},
{
"$sort": { "lastModifDate": -1 }
},
{
"$limit": 1
}
])
Output
/* 1 */
{
"result" : [
{
"_id" : ObjectId("5547e45c97d8b2c816c994c8"),
"actualPrice" : 19500,
"lastModifDate" : ISODate("2015-05-04T22:53:50.583Z"),
"price" : 16000
}
],
"ok" : 1
}
#1
You could try the following aggregation pipeline which does not need to make use of the $group
operator stage as the $project
operator takes care of the fields projection:
您可以尝试以下聚合管道,它不需要使用$ group运算符阶段,因为$ project运算符负责字段投影:
db.adds.aggregate([
{
"$match": {"addID": "1746540"}
},
{
"$unwind": "$history"
},
{
"$project": {
"actualPrice": 1,
"lastModifDate": "$history.modifDate",
"price": "$history.price"
}
},
{
"$sort": { "lastModifDate": -1 }
},
{
"$limit": 1
}
])
Output
/* 1 */
{
"result" : [
{
"_id" : ObjectId("5547e45c97d8b2c816c994c8"),
"actualPrice" : 19500,
"lastModifDate" : ISODate("2015-05-04T22:53:50.583Z"),
"price" : 16000
}
],
"ok" : 1
}