从 mongo 的子数组中查找特定值

Question

我只想从

{
        "_id" : "625305190f48a6512a18220d",
        "artist" : "AC/DC",
        "albums" : [
                {
                        "title" : "High Voltage",
                        "year" : 1976
                },
                {
                        "title" : "Back in Black",
                        "year" : 1980
                },
                {
                        "title" : "Dirty Deeds Done Dirt Cheap",
                        "year" : 1976
                },
                {
                        "title" : "Highway to Hell",
                        "year" : 1979
                }
        ],
        "singers" : "Bon Scott"
}

我首先尝试插入的

db.getCollection('first').insertMany([])

数据中获取 1976 年的值，然后使用以下语句过滤掉 1976 年以下代码

db.first.findOne({"albums.year":1976})

并得到此输出：

{
        "_id" : "625305190f48a6512a18220d",
        "artist" : "AC/DC",
        "albums" : [
                {
                        "title" : "High Voltage",
                        "year" : 1976
                },
                {
                        "title" : "Back in Black",
                        "year" : 1980
                },
                {
                        "title" : "Dirty Deeds Done Dirt Cheap",
                        "year" : 1976
                },
                {
                        "title" : "Highway to Hell",
                        "year" : 1979
                }
        ],
        "singers" : "Bon Scott"
}

为什么它给出的年份不是 1976 年 我只想过滤1976 年

Answer 1

$ project之后查找

db.collection.find({
  "albums.year": 1976
},
{
  "albums.$": 1
})

mongoplay