我有几个文档看起来像这样:
{
"_id" : ObjectId("50b59cd75bed76f46522c34e"),
"player_id" : 0,
"league_id" : 2,
"results" : [
{ "discipline" : "football",
"score" : 25.15
},
{
"discipline" : "basketball",
"score" : 21.24
},
{
"discipline" : "cycling",
"score" : 68.19
},]
}
我尝试聚合这些数据 . 首先 unwind 结果数组,然后只留下“ football " and " cycling ”,下次计数 average 结果 . 这部分我做了,它正在工作 . 我的代码:
db.grades.aggregate(
{$unwind:"$results"},
{$match: {$or: [{"results.discipline":"football"},{"results.discipline":"cycling"} ]}},
{$group:{_id:{player_id:"$player_id",league_id:"$league_id"}, 'average':{$avg:"$results.score"}}},
)
然后我尝试聚合 league_id ,这意味着,普通玩家在特定联赛中的结果,添加到上面的代码: {$group:{_id:"$_id.league_id",aver_league:{$avg:$average}}}
现在代码看起来像:
db.grades.aggregate(
{$unwind:"$results"},
{$match: {$or: [{"results.discipline":"football"},{"results.discipline":"cycling"} ]}},
{$group:{_id:{player_id:"$player_id",league_id:"$league_id"}, 'average':{$avg:"$results.score"}}},
{$group:{_id:"$_id.league_id",aver_league:{$avg:$average}}}
)
控制台显示: JavaScript execution failed: ReferenceError: $average is not defined.
有什么问题?我在哪里弄错了?可以通过 _id.league_id
汇总吗?
1 回答
试试这个管道:
它适用于我的文档:
UPD. 如果要再次分组,请 league_id :