[英]Querying an embedded document in MongoDB
我有一個Bson,下面的結構帶有一些嵌入式文檔。 我想知道如何在特定日期獲取變量的值(“ 2014-08-09”:53.0)或廣告資源的值(“ 2014-08-09”:0.0) 。
{
"_id" : ,
"last_modified" : "",
"client" : "",
"credentials" : [],
"tags" : [],
"variables" : [
{
"name" : "sales",
"_values" : {
"2014-08-09" : 53.0,
...
},
"tags" : [],
"is_target" : true,
"method1" : "",
"method2" : "",
"vtype" : ,
"index_type" :
},
{
"name" : "inventory",
"_values" : {
"2014-08-09" : 0.0,
...
},
"tags" : [],
"is_target" : ,
"method1" : "",
"method2" : "",
"vtype" : ,
"index_type" :
},
{
"name" : "price",
"_values" : {},
"tags" : [],
"is_target" : ,
"method2" : "",
"method1" : "",
"vtype" : ,
"index_type" :
}
}
}
嘗試使用mongodb聚合框架https://docs.mongodb.com/manual/reference/operator/aggregation/
db.mycol.aggregate([
{"$unwind":"$variables"},
{$project:{"date":"$variables._values.2014-08-09"}}
])
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