node.js - 查询深度嵌套数组中的属性

Question

所以我在类(class)集中有这个文档

{
 "_id" : ObjectId("53580ff62e868947708073a9"),
    "startDate" : ISODate("2014-04-23T19:08:32.401Z"),
    "scoreId" : ObjectId("531f28fd495c533e5eaeb00b"),
    "rewardId" : null,
    "type" : "certificationCourse",
    "description" : "This is a description",
    "name" : "testingAutoSteps1",
    "authorId" : ObjectId("532a121e518cf5402d5dc276"),
    "steps" : [ 
        {
            "name" : "This is a step",
            "description" : "This is a description",
            "action" : "submitCategory",
            "value" : "532368bc2ab8b9182716f339",
            "statusId" : ObjectId("5357e26be86f746b68482c8a"),
            "_id" : ObjectId("53580ff62e868947708073ac"),
            "required" : true,
            "quantity" : 1,
            "userId" : [ 
                ObjectId("53554b56e3a1e1dc17db903f")
            ]
        },...

我想做的是创建一个查询，返回在 steps 的 userId 数组中具有特定 userId 的所有类(class)> 特定 userId 的数组。我试过像这样使用 $elemMatch

Course.find({ 
    "steps": { 
        "$elemMatch": { 
            "userId": { 
                "$elemMatch": "53554b56e3a1e1dc17db903f"
            }
        }
    }
},

但它似乎返回一个空文档。

Answer 1

我认为这对你有用，你的语法有点偏离，而且你需要使用 ObjectId():

db.Course.find({ steps : { $elemMatch: { userId:ObjectId("53554b56e3a1e1dc17db903f")} } })