Question

我在mongo中有一个像这样的值

{ id: Mongo ID,
  Match_Type: Challenge Match,
  Match_Number: 0001
  Challenging_Player: Mark,
  Challenged_Player: John,
}
{ id: Mongo ID,
  Match_Type: Challenge Match,
  Match_Number: 0002
  Challenging_Player: John,
  Challenged_Player: Bob
}

名称可以出现在Challenging Player或Challenged Player的两列中。我正在尝试进行汇总，以找出参加挑战赛次数最多的玩家。这意味着我需要一个既有挑战性又有挑战性的球员分组。

有人可以帮忙吗？

Answer 1

db.getCollection('the_collection').aggregate([
  {$match: { Match_Type: "Challenge Match"}},
  { $project: { players: { $setUnion: [ ["$Challenging_Player"], ["$Challenged_Player"] ] } }},
  { "$unwind" : "$players"},
  {$group : { _id:"$players", count:{$sum:1} } }
  ])

Answer 2

   db.<yourcollection>.aggregate( [
     { $project  : { players: ["$Challenging_Player", "$Challenged_Player"]}},
     { "$unwind" : "$players"},
     { "$group"  : {"_id" : "$players", "count" : {"$sum" : 1}}}
   ] )

我要将您的每个文档都分解为2个文档，每个玩家一个，然后按该字段分组

Mongodb聚合，与分组依据混淆

2 个答案: