$在mongodb中查找多个级别

Posted 2023-03-10

【中文标题】$在mongodb中查找多个级别

【英文标题】：$lookup multiple levels in mongodb

【发布时间】：2019-03-01 23:35:04

【问题描述】：

我是 mongodb 的新手，我使用 mongoose populate 编写了查询。

this.model.findById( _id: req.params.id )
.populate('potentialLevels', 'description result plIndex')
.populate(
  path: 'categories',
  select: 'name',
  populate: 
    path: 'tasks',
    model: 'Task',
    select: '-createdAt -updateAt -start -end -userEstEnd',
    populate: [
      path: 'potentialLevelId',
      model: 'PotentialLevel',
      select: 'description result plIndex'
    , 
      path: 'tasks',
      model: 'Task',
      select: 'name',
      options:  sort:  'priority': 1  
    ]
  
)

上述查询有效，它返回以下数据：

"categories":["tasks":[],"_id":"5b56b9ca03dbaf1ee804a334","name":"Relationship","tasks":["estMin":75,"totEstMin":72,"totFocusBlock":2.4,"perDayTotEstMin":12,"perDayTotFocusBlock":0.4,"dueDays":6,"priority":0.031746031746031744,"status":"CREATED","tasks":["_id":"5b9f71a32b264f001592d59b","name":"Market it"],"_id":"5b9f712a2b264f001592d595","cx":18.82748286757155,"cy":-48.04254248966534,"name":"Rent 14M","categoryId":"5b56b9ca03dbaf1ee804a335","potentialLevelId":"_id":"5b56b7bab926429370bb5035","description":"Big, Long terms Positive Reward","plIndex":2,"result":9,"updatedAt":"2018-09-17T17:11:20.657Z","__v":1,"childViewId":"5b9f719e2b264f001592d59a","estMin":20,"totEstMin":240,"totFocusBlock":8,"perDayTotEstMin":5.714285714285714,"perDayTotFocusBlock":0.1904761904761905,"dueDays":42,"priority":0.01511715797430083,"status":"CREATED","tasks":["_id":"5b9fcf7d97e5ea00158c010b","name":"ijg[f"],"_id":"5b9fcf3c97e5ea00158c0105","cx":43.25128613351225,"cy":-23.764442930501236,"name":"Build online biz £10k","categoryId":"5b56b9ca03dbaf1ee804a335","potentialLevelId":"_id":"5b56b7bab926429370bb5035","description":"Big, Long terms Positive Reward","plIndex":2,"result":9,"updatedAt":"2018-09-17T17:11:20.411Z","__v":1,"childViewId":"5b9fcf7597e5ea00158c010a"],"_id":"5b56b9ca03dbaf1ee804a335","name":"Work","tasks":["estMin":60,"totEstMin":72,"totFocusBlock":2.4,"perDayTotEstMin":1.309090909090909,"perDayTotFocusBlock":0.04363636363636363,"dueDays":55,"priority":0.003463203463203463,"status":"CREATED","tasks":[],"_id":"5b9fceb797e5ea00158c0104","cx":40.06629027106884,"cy":28.811714352229274,"name":"Explore corp sub model","categoryId":"5b56b9ca03dbaf1ee804a336","potentialLevelId":"_id":"5b56b7bab926429370bb5035","description":"Big, Long terms Positive Reward","plIndex":2,"result":9,"updatedAt":"2018-09-17T15:58:25.889Z","__v":0,"estMin":0,"totEstMin":0,"totFocusBlock":0,"perDayTotEstMin":0,"perDayTotFocusBlock":0,"dueDays":0,"priority":0,"status":"CREATED","tasks":[],"_id":"5ba0f173c2d9810015ad3e0c","cx":282.75602123836603,"cy":133.17858293828135,"name":"kjg;hk","categoryId":"5b56b9ca03dbaf1ee804a336","potentialLevelId":"_id":"5b56b7bab926429370bb503d","description":"Tiny, short-lasting Positive reward","plIndex":10,"result":1,"updatedAt":"2018-09-18T12:37:07.974Z","__v":0],"_id":"5b56b9ca03dbaf1ee804a336","name":"Fun","tasks":[],"_id":"5b56b9ca03dbaf1ee804a337","name":"Health"],"events":[],"potentialLevels":["_id":"5b56b7bab926429370bb5034","description":"Massive Life-long Positive Reward","plIndex":1,"result":10,"_id":"5b56b7bab926429370bb5035","description":"Big, Long terms Positive Reward","plIndex":2,"result":9,"_id":"5b56b7bab926429370bb5036","description":"Medium long-term Positive Reward","plIndex":3,"result":8,"_id":"5b56b7bab926429370bb5037","description":"Small long Positive reward","plIndex":4,"result":7,"_id":"5b56b7bab926429370bb5038","description":"Big Medium term Positive reward","plIndex":5,"result":6,"_id":"5b56b7bab926429370bb5039","description":"Medium sized, Medium term Positive reward","plIndex":6,"result":5,"_id":"5b56b7bab926429370bb503a","description":"Small Medium-term Positive reward","plIndex":7,"result":4,"_id":"5b56b7bab926429370bb503b","description":"Big short-lasting Positive reward","plIndex":8,"result":3,"_id":"5b56b7bab926429370bb503c","description":"Small short-lasting Positive reward","plIndex":9,"result":2,"_id":"5b56b7bab926429370bb503d","description":"Tiny, short-lasting Positive reward","plIndex":10,"result":1],"_id":"5b56b9ca03dbaf1ee804a338","__v":0,"createdAt":"2018-07-24T05:31:54.598Z","name":"Capture GUI","updatedAt":"2018-07-24T05:31:54.598Z","userId":"5b4db45839adf5cbe5496b90","viewType":"CAPTURE"

现在我想要使用聚合管道进行相同的查询。我试过下面的代码，但它不起作用。

db.View.aggregate([
  "$match":  "viewType": "CAPTURE", "userId": ObjectId("5b4db45839adf5cbe5496b90")  ,
 "$lookup": "from": "PotentialLevel", "localField": "potentialLevels", "foreignField": "_id", "as": "potentialLevels",
  "$lookup": "from": "Category", "localField": "categories", "foreignField": "_id", "as": "categories",
  "$unwind": "path":"$categories", "preserveNullAndEmptyArrays": true ,
  "$lookup": "from": "Task", "localField": "categories.tasks", "foreignField": "_id", "as": "categories.tasks",
  "$group":  "_id": "$_id", "name": "$first": "$name",  "potentialLevels": "$first": "$potentialLevels", "categories": "$push": "$categories"
])

上面的查询已经完成了一半。我无法为使用聚合的深度填充编写查询。请帮我。谢谢

【问题讨论】：

您能否发布您正在使用的所有集合和版本的 mongodb 的示例数据

您可以获取任何样本数据和参考表。我只想要深层次的查找。我已经为填充查询添加了示例数据。

我也需要你的 mongodb 版本

【参考方案1】：

您可以在 mongodb 3.6 及更高版本中尝试以下聚合

this.model.aggregate([
   "$match":  "_id": mongoose.Types.ObjectId(req.params.id) ,
   "$lookup": 
    "from": PotentialLevels.collection.name,
    "let":  "potentialLevels": "$potentialLevels" ,
    "pipeline": [
       "$match":  "$expr":  "$in": [ "$_id", "$$potentialLevels" ]   ,
       "$project":  "description": 1, "result": 1, "plIndex": 1 
    ],
    "as": "potentialLevels"
  ,
   "$lookup": 
    "from": Categories.collection.name,
    "let":  "categories": "$categories" ,
    "pipeline": [
       "$match":  "$expr":  "$in": [ "$_id", "$$categories" ]   ,
       "$lookup": 
        "from": Tasks.collection.name,
        "let":  "tasks": "$tasks" ,
        "pipeline": [
           "$match":  "$expr":  "$in": [ "$_id", "$$tasks" ]   ,
           "$lookup": 
            "from": PotentialLevels.collection.name,
            "let":  "potentialLevelId": "$potentialLevelId" ,
            "pipeline": [
               "$match":  "$expr":  "$eq": [ "$_id", "$$potentialLevelId" ]   ,
               "$project":  "description": 1, "result": 1, "plIndex": 1 
            ],
            "as": "potentialLevelId"
          ,
           "$lookup": 
            "from": Tasks.collection.name,
            "let":  "tasks": "$tasks" ,
            "pipeline": [
               "$match":  "$expr":  "$in": [ "$_id", "$$tasks" ]   ,
               "$sort":  "priority": 1  ,
               "$project":  "name": 1 
            ],
            "as": "tasks"
          ,
           "$unwind": "$potentialLevelId" ,
           "$project":  "createdAt": 1, "updateAt": 1, "start": 1, "end": 1, "userEstEnd": 1, "tasks": 1, "potentialLevelId": 1 
        ],
        "as": "tasks"
      ,
       "$project":  "name": 1, "tasks": 1 
    ],
    "as": "categories"
  
])

【讨论】：

我已经尝试过这种方式，但由于 mongodb 版本，它不起作用。我已经更新了我的 mongodb 版本。谢谢

如果你需要冗长的解释，你可以通过这个***.com/questions/49953780/…