我有一个MongoDB查询，我想弄明白。我想按日期和另一个字段(投资组合)对我的数据进行分组，并获取该分组中每个buildResult的计数。示例数据如下所示:{"_id":ObjectId("52dea764e4b0a491abb54102"),"type":"build","time":ISODate("2014-01-21T16:59:16.642Z"),"data":{"buildNumber":35,"buildDuration":1034300,"portfolio":"Shared","buildResult":"FAILURE"}}{"_id":ObjectId("52

我正在尝试根据计算字段计算MongoDB查询中的百分比-不确定这是否可能。我希望能够做的是计算失败百分比:(failedcount/total)*100以下是一些示例文档:{"_id":ObjectId("52dda5afe4b0a491abb5407f"),"type":"build","time":ISODate("2014-01-20T22:39:43.880Z"),"data":{"buildNumber":30,"buildResult":"SUCCESS"}},{"_id":ObjectId("52dd9fede4b0a491abb5407a"),"type":"build