非常使用的mongodb的聚合函數（使用SpringDataMongoDb）

下面這一段就是用java代碼來實現mongodb的聚合函數aggrega.

 Aggregation agg = Aggregation.newAggregation(  
	                Aggregation.match(criteria),//條件
	                Aggregation.group("a","b","c","d","e").count().as("f"),//分組字段  
	                Aggregation.sort(sort),//排序
	                Aggregation.skip(page.getFirstResult()),//過濾
	                Aggregation.limit(pageSize)//頁數
				 );  
	        AggregationResults<Test> outputType=mongoTemplate.aggregate(agg,"test",Test.class);  
	        List<Test> list=outputType.getMappedResults();

mongodb原語句：

db.getCollection('test').aggregate( [
                        { $match : { score : { $gt : 70, $lte : 90 } } },
                        { $group: { _id: null, count: { $sum: 1 } } },
                        { $sort:a},
                        { $skip:10},
                        { $limit:10}
                        ] );

類似於sql

select a,b,c,count(1) from test where ... group by (...)