I want to get Descending order data by date on playDate Attribute, but descending condition is apply on gameName : hockey object

Data

[
  {
    "gameDetails": [
      {
        "gameName": "hockey",
        "playDate": "2014-05-05T00:00:00.000Z"
      },
      {
        "gameName": "football",
        "playDate": "2022-06-05T00:00:00.000Z"
      }
    ]
  },
  {
    "gameDetails": [
      {
        "gameName": "hockey",
        "playDate": "2020-05-05T00:00:00.000Z"
      },
      {
        "gameName": "cricket",
        "playDate": "2013-06-05T00:00:00.000Z"
      }
    ]
  },
  {
    "gameDetails": [
      {
        "gameName": "cricket",
        "playDate": "2013-05-05T00:00:00.000Z"
      },
      {
        "gameName": "football",
        "playDate": "2021-06-05T00:00:00.000Z"
      }
    ]
  },
  {
    "gameDetails": [
      {
        "gameName": "cricket",
        "playDate": "2009-05-05T00:00:00.000Z"
      },
      {
        "gameName": "hockey",
        "playDate": "2021-06-05T00:00:00.000Z"
      }
    ]
  }
]

From above data we have to output gave records gameName:hockey which is present in gameDetail Array ,in descending order by playDate attribute of gameName:hockey object

Output is:

[
  {
    "gameDetails": [
      {
        "gameName": "cricket",
        "playDate": "2009-05-05T00:00:00.000Z"
      },
      {
        "gameName": "hockey",
        "playDate": "2021-06-05T00:00:00.000Z"
      }
    ]
  },
  {
    "gameDetails": [
      {
        "gameName": "hockey",
        "playDate": "2020-05-05T00:00:00.000Z"
      },
      {
        "gameName": "cricket",
        "playDate": "2013-06-05T00:00:00.000Z"
      }
    ]
  },
  {
    "gameDetails": [
      {
        "gameName": "hockey",
        "playDate": "2014-05-05T00:00:00.000Z"
      },
      {
        "gameName": "football",
        "playDate": "2022-06-05T00:00:00.000Z"
      }
    ]
  }
]

CodePudding user response：

One option is:

1. Keep only documents with a hockey game
2. Set hockeyData with the first hockey item per each document
3. $sort and format

db.collection.aggregate([
  {$match: {gameDetails: {$elemMatch: {gameName: "hockey"}}}},
  {$set: {hockeyData: {
        $first: {$filter: {
            input: "$gameDetails",
            cond: {$eq: ["$$this.gameName", "hockey"]}
        }}
  }}},
  {$sort: {"hockeyData.playDate": -1}},
  {$unset: "hockeyData"}
])

See how it works on the playground example

CodePudding user response：

you can either use the $sortArray or sort outside of the database by adding that condition to your sorting function.

  var arr = your array
  var result = arr.sort(function (a, b) {
  var aDate = new Date(a.gameDetails[0].playDate);
  var bDate = new Date(b.gameDetails[0].playDate);
  if (
    a.gameDetails[0].gameName == "hockey" &&
    b.gameDetails[0].gameName == "hockey"
  ) {
    return bDate - aDate;
  } else {
    return aDate - bDate;
  }
})