go mongodb Pipeline 聚合查询格式

//类似于$sum的操作还有很多，比较常用的是$min(求最小值)，$max(求最大值)  查询条件  match  和聚合 group 查询一定要注意顺序 
aggregate := mongo.Pipeline{
		bson.D{
			{"$match" ,bson.D{
				{ "season_id", seasonId},
				{"data_source_at",bson.M{"$gte": start}},
				{"data_source_at",bson.M{"$lte": end}}},
			},
		},
		bson.D{
			{"$group", bson.D{
				{"_id", "$student_id"},
				{"win_count", bson.D{
					{"$sum", "$win_count"},
				}},
				{"school_id", bson.D{
					{"$first", "$school_id"},
				}},
			}},
		},

	}

//另外一种写法

aggregate := mongo.Pipeline{
   {
      {"$match" ,bson.D{
         { "season_id", seasonId},
         {"data_source_at",bson.M{"$gte": start}},
         {"data_source_at",bson.M{"$lte": end}},
      },
      },
   },
   {
      {"$group", bson.D{
         {"_id", "$student_id"},
         {"win_count", bson.D{
            {"$sum", "$win_count"},
         }},
         {"up_star", bson.D{
            {"$sum", "$up_star"},
         }},
      }},
   },

}