2. mongodb Aggregation 语法

1. 分组统计

Criteria criteria = Criteria.where("userId").is(userId)
                .and("stage").is(stage)
                .and("ifFreeGoods").is(true)
                .and("createTime").gte(time);
        Aggregation aggregation = Aggregation.newAggregation(Aggregation.match(criteria),
                Aggregation.group("lessonId").sum("playCount").as("playCount"),
                Aggregation.project()
                        .and("_id").as("lessonId")
                        .and("playCount").as("playCount")
        );
        AggregationResults<BasicDBObject> aggregationResults = mongoTemplate.aggregate(
                aggregation, CoursePlayStatisticsEntity.class, BasicDBObject.class
        );
        if (Objects.isNull(aggregationResults) || CollectionUtils.isEmpty(aggregationResults.getMappedResults())) {
            return 0L;
        }
        List<BasicDBObject> results = aggregationResults.getMappedResults();
        return results.stream().mapToLong(e -> {
            return e.getLong("playCount");
        }).sum();

 2. 不分组统计

如果不分组获取统计值,那么只是需要将  group  分组传 空

Criteria criteria = Criteria.where("userId").is(userId)
                .and("stage").is(stage)
                .and("ifFreeGoods").is(true)
                .and("createTime").gte(time);
        Aggregation aggregation = Aggregation.newAggregation(Aggregation.match(criteria),
                Aggregation.group().sum("playCount").as("playCount"),
                Aggregation.project()
                        .and("playCount").as("playCount")
        );
        AggregationResults<BasicDBObject> aggregationResults = mongoTemplate.aggregate(
                aggregation, CoursePlayStatisticsEntity.class, BasicDBObject.class
        );
        if (Objects.isNull(aggregationResults) || CollectionUtils.isEmpty(aggregationResults.getMappedResults())) {
            return 0L;
        }
        List<BasicDBObject> results = aggregationResults.getMappedResults();
        return results.stream().mapToLong(e -> {
            return e.getLong("playCount");
        }).sum();

 3. 条件查询，结果处理

db.ussi.aggregate(
    [
        {
            $match: {
                tsct: {
                    $gte: 1514736000000
                },
                wcts: {
                    $gt: 0
                }
            }
        },
        {
            $project: {
                butp: 1,
                uid: 1,
                tsct: 1,
                wcts2S: {
                    "$ifNull": ["$wcts", 0]
                },
                "divide": {
                    "$divide": [{
                        "$ifNull": ["$wcts", 0]
                    }, 60]
                },
                date2Str: {
                    $dateToString: {
                        format: "%Y-%m-%d %H:%M:%S",
                        date: {
                            "$add": [new Date(0), "$tsct", 28800000]
                        }
                    }
                }
            }
        },
        {
            $sort: {
                wcts2S:  - 1
            }
        }
    ]
)

包含：
1. tsct 日期格式化
2. wcts 非空判断，除 60 处理
3. sort 排序

 

参考资料，管道聚合计算：https://www.bbsmax.com/A/E35pL2e85v/