Question 206069 in Mongodb Question posted in
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I find function FIELD in mongodb

I want sort in mongodb like "order by FIELD (id, 1,3,7,8)" of mysql.

My data mongo:

* Id1: 6281c8499f2dd7e9719a780d, name : "aaa",
* Id2: 6112c8499f2dd7e9719a780d, name : "asc",
* Id3: 628dd1b4fc0fd54971b87e17, name : "123"
* ...

Code:

db.getCollection("experts").find(
    {
        "_id" : {
            "$in" : [
                ObjectId("628dd1b4fc0fd54971b87e17"),
                ObjectId("6281c8499f2dd7e9719a780d"),
                ObjectId("6112c8499f2dd7e9719a780d"),
               ....
            ]
        }
    }
).sort( ???? );

Obtained result:

"628dd1b4fc0fd54971b87e17", 
"6281c8499f2dd7e9719a780d",
"6112c8499f2dd7e9719a780d"

Expected result:

* Id3: 628dd1b4fc0fd54971b87e17, name : "123"
* Id1: 6281c8499f2dd7e9719a780d, name : "aaa"
* Id2: 6112c8499f2dd7e9719a780d, name : "asc"

Dont sort field name I need sort field ID allow position array $in

Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0

    Thanks all,

    I think this solution. And work :D

    db.getCollection("experts").aggregate(
    [
        {
            "$match" : {
                "_id" : {
                    "$in" : [
                        ObjectId("628490ec4995322a26201e2a"),
                        ObjectId("6281c8499f2dd7e9719a780d"),
                        ObjectId("6112c8499f2dd7e9719a780d")
                    ]
                }
            }
        }, 
        {
            "$project" : {
                "_id" : 1.0,
                "index" : {
                    "$indexOfArray" : [
                        [
                            ObjectId("628490ec4995322a26201e2a"),
                            ObjectId("6281c8499f2dd7e9719a780d"),
                            ObjectId("6112c8499f2dd7e9719a780d")
                        ],
                        "$_id"
                    ]
                }
            }
        }, 
        {
            "$sort" : {
                "index" : NumberInt(1)
            }
        }
    ]
);

  2. 0

    As stated in my comment, this is not possible due to the nature of JSON documents. However, you can use a workaround like this:

    db.collection.aggregate([
   { $project: { data: { $objectToArray: "$$ROOT" } } },
   {
      $set: {
         data: {
            $sortArray: { input: "$data", sortBy: { k: 1 } }
         }
      }
   },
   {
      $set: {
         // positions start at index 0
         sortKey1: { $arrayElemAt: ["$data", 0] },
         sortKey2: { $arrayElemAt: ["$data", 2] },
         sortKey3: { $arrayElemAt: ["$data", 6] },
         sortKey4: { $arrayElemAt: ["$data", 7] }
      }
   },
   {
      $sort: {
         "sortKey1.v": 1,
         "sortKey2.v": 1,
         "sortKey3.v": 1,
         "sortKey4.v": 1
      }
   },
   { $replaceWith: { $arrayToObject: "$data" } }
])

    Mongo Playground

    Note, usually it is a bad design to store numeric values as string. Check Ascending/Descending Sort whether the sorting algorithm matches your requirements.

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