Question

我正在尝试使用elemMatch基于嵌套在数组和第二个数组中的值查询集合和过滤器。

{
"email": "user1@email.com",
"project" [ {
                projectId: ObjectId("123"),
                preference: [
                            {"name": "name1", "value": true},
                            {"name": "name2", "value": false}
                ]
            }, 
            {
                projectId: ObjectId("456"),
                preference: [
                            {"name": "name1", "value": true},
                            {"name": "name2", "value": true}
                ]
            }
]
}, 
{
"email": "user2@email.com",
"project" [ {
                projectId: ObjectId("123"),
                preference: [
                            {"name": "name1", "value": false},
                            {"name": "name2", "value": true}
                ]
            }, 
            {
                projectId: ObjectId("456"),
                preference: [
                            {"name": "name1", "value": true},
                            {"name": "name2", "value": true}
                ]
            }
]
}

我尝试了几种不同的变体，将以下两个查询合并为一个，以尝试实现我的返回目标。

{email：“ user1@email.com”}

db.user.find({"project":{"$elemMatch":{"projectId":ObjectId("123")}}}, {email: 1})
db.user.find({"project.preference":{"$elemMatch":{"$and":[{"name":"name1"}, {"value": true}]}}}, {email: 1})

Answer 1

您可以使用$unwind简化查询多层嵌套数组的操作，请尝试：

db.user.aggregate([
    {  $unwind: "$project" },
    {  $match: { "project.projectId": "123" } },
    {  $unwind: "$project.preference" },
    {  $match: { "project.preference.name": "name1", "project.preference.value": true } },
    {  $project: { _id: 0, email: 1 } }
])

查询ElemMatch数组中的数组

1 个答案: