我试图在文档中检索一些嵌入式数组的查找数据。
这是数据的示例:
{
"_id": "58a4fa0e24180825b05e14e9",
"fullname": "Test User",
"username": "testuser"
"teamInfo": {
"challenges": [
{
"levelId": "5e14e958a4fa0",
"title": "test challenge 1.1"
},
{
"levelId": "5e14e958a4fa0",
"title": "test challenge 1.2"
},
{
"levelId": "5e14e958a4fa1",
"title": "test challenge 2.1"
}
]
}
}
如您所见,TeamInfo.Challenges是一个数组,包含LevelID字段。这些指向另一个称为级别的集合中的_id字段。
但是我该如何处理这样的响应?
{
"_id": "58a4fa0e24180825b05e14e9",
"fullname": "Test User",
"username": "testuser"
"teamInfo": {
"challenges": [
{
"levelInfo": {
"name": "Level 1"
},
"title": "test challenge 1.1"
},
{
"levelInfo": {
"name": "Level 1"
},
"title": "test challenge 1.2"
},
{
"levelInfo": {
"name": "Level 2"
},
"title": "test challenge 2.1"
}
]
}
}
我尝试使用Undind,Project和Group。但是我很困惑。
const user = await User.aggregate([
{
$match: {_id: new mongoose.Types.ObjectId(req.user.userId)}
},
{
$lookup: {
from: 'levels',
localField: 'teamInfo.challenges.levelId',
foreignField: '_id',
as: 'challLevelInfo'
}
},
{
$group: {
_id: "$_id",
........IM CONFUSED HERE........
}
}
]);
您可以使用查找管道来处理嵌套查找
const pipeline = [
{
$match: {_id: new mongoose.Types.ObjectId(req.user.userId)}
},
{
$lookup: {
from: 'levels',
let: { level_id: "$teamInfo.challenges.levelId" },
pipeline: [
{
$match: {
$expr: {
$eq: ["$_id", "$$level_id"]
}
}
},
{
$lookup: {
from: '<level collection>',
localField: "levelId",
foreignField: "_id",
as: "levelInfo"
}
},
{
$project: {
levelInfo: {
name: "$levelInfo.name"
}
title: 1
}
}
],
as: "challenges"
},
},
{ $project: {
_id: 1,
fullname: 1,
username: 1,
teamInfo: {
challenges: "$challenges"
}
}}
]
const result = await User.Aggregate(pipeline)
希望这个帮助!