How do I only return documents that return the conditional true if every item in the array tests tru-CodePudding

I Have tried using the $all operator and the $and operator and still can't make any progress

I want to only return the documents that every item in the ratings array is greater than 8 and less than 10

Here are my example documents:

This is the query I am trying to run:

db.Practicelab2.find({ratings: {$elemMatch:{$gt:8, $lt:10}}})

{ _id: ObjectId("6331c8407a386c3c9bd9f976"),
  title: 'The Last Student Returns',
  meta: { rating: 9.5, aired: 2018, runtime: 100 },
  visitors: 1300000,
  expectedVisitors: 1550000,
  genre: [ 'thriller', 'drama', 'action' ],
  ratings: [ 10, 9 ] }

{ _id: ObjectId("6331c8407a386c3c9bd9f977"),
  title: 'Supercharged Teaching',
  meta: { rating: 9.3, aired: 2016, runtime: 60 },
  visitors: 370000,
  expectedVisitors: 1000000,
  genre: [ 'thriller', 'action' ],
  ratings: [ 10, 9, 9 ] }

CodePudding user response：

You can chain up $allElementsTrue and $map with your conditions. The idea is to create a boolean array with $map. Use $allElementsTrue on the resulting boolean array to perform the filtering.

db.collection.find({
  $expr: {
    $eq: [
      true,
      {
        "$allElementsTrue": {
          "$map": {
            "input": "$ratings",
            "as": "r",
            "in": {
              $and: [
                {
                  $gt: [
                    "$$r",
                    8
                  ]
                },
                {
                  $lt: [
                    "$$r",
                    10
                  ]
                }
              ]
            }
          }
        }
      }
    ]
  }
})

Here is the Mongo playground for your reference.