mongo與java 的group by分組和排序程式碼(備忘)
阿新 • • 發佈:2019-01-09
MongoTemplate gameMt = (根據具體專案獲得)
DBCollection myColl = gameMt.getDb().getCollection("avatar");//表名
// 分組
DBObject groupFields = new BasicDBObject("_id", "$level");// level為資料庫中的欄位,即要進行分組的依據
// 對應的個數
groupFields.put("count", new BasicDBObject("$sum", 1));
DBObject group = new BasicDBObject("$group", groupFields);
// 排序
DBObject sortFields = new BasicDBObject("_id", 1);//根據_id升序
DBObject sort = new BasicDBObject("$sort", sortFields);
AggregationOutput output = myColl.aggregate(group, sort);
Iterable<DBObject> result = output.results();