文章目录
		
			
		
		
		
		mongodb求和
Aggregation

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 | db.publicFoundation.aggregate([{
 $match:{acceptDate:{$ne:null}}
 },
 {
 $group:{'_id':null,"count":{'$sum':'$money'}},
 }
 ]);
 
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 | DBObject match = new BasicDBObject();DBObject acceptDate = new BasicDBObject();
 acceptDate.put("$ne", null);
 match.put("acceptDate", acceptDate);
 DBObject db = new BasicDBObject(new BasicDBObject("$match", match));
 DBObject object = new BasicDBObject();
 DBObject group = new BasicDBObject();
 object.put("_id", null);
 object.put("count", new BasicDBObject("$sum", "$money"));
 group.put("$group", object);
 AggregationOutput output = mongoTemplate.getCollection("publicFoundation").aggregate(db, group);
 Iterator iterator = output.results().iterator();
 DBObject redult = null;
 int totalMoney = 0;
 while (iterator.hasNext()) {
 redult = (DBObject) iterator.next();
 totalMoney = (int)redult.get("count");
 }
 
 | 
db.mapReduce.insert([
    {name:"jay",age:20},
    {name:"mike",age:21}
]);
    
db.mapReduce.find();
    
db.mapReduce.mapReduce(
     function(){
        emit(this.age,this.age);
    },
    function(key,value){
        return Array.sum(value)
    },
    {
            //query:{age:},
            out:"age"
    }
    
);