Mongo在嵌套对象中查找一组字段

Question

我在mongo db中有一个以下结构

{
    "_id" : ObjectId("58e8d3323fe482ef368b4567"),
    "productId" : "poe10001134",
    "batchdetails" : [ 
        {
            "batchidId" : "BD0166",
            "batchno" : "BbfN-1444-SBRPX"
         },
        {
            "batchidId" : "BD0167",
            "batchno" : "Bff-8444-kfkff"
         },
         {
            "batchidId" : "BD01447",
            "batchno" : "Bff-8415-kfkff"
         }
]
}

我想实现以下结果

＆＃34;的productId＆＃34; ：＆＃34; poe10001134＆＃34;

＆＃34; batchno＆＃34; ：＆＃34; Bff-8415-kfkff＆＃34;

当我执行以下查询

时

db.getCollection('table').findOne( {"batchdetails.batchidId" : "BD01447"},{productId:1,"batchidId.batchno":1})

它返回所有批次没有

＆＃34;的productId＆＃34; ：＆＃34; poe10001134＆＃34;

＆＃34; batchno＆＃34; ：＆＃34; BbfN-1444-SBRPX＆＃34;

＆＃34; batchno＆＃34; ：＆＃34; Bff-8444-kfkff＆＃34;

＆＃34; batchno＆＃34; ：＆＃34; Bff-8415-kfkff＆＃34;

Answer 1

这样做：

db.getCollection('table').findOne( {"batchdetails.batchidId" : "BD01447"},
    {productId:1,"batchidId.batchno.$":1})

投影中的$包含查询中匹配的batchno数组元素的索引。