记录问题：在es中按天分组然后去重统计条数。
例：统计每天 每月的签到人数，用户签到一次存到es中，数据可能有重复签到，统计时需要去重。

怎么去解决这个去重问题呢？只需要在es桶中加入去重子桶即可。

		//查询条件
        BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();
        TermQueryBuilder termQuery = QueryBuilders.termQuery("id", id);
        boolQueryBuilder.must(termQuery);
        //去重
        CardinalityAggregationBuilder aggregationBuilder = AggregationBuilders.cardinality("count").field("id")
        //按天分桶
        DateHistogramAggregationBuilder aggs = AggregationBuilders
	        .dateHistogram("day")
	        .field("reportDateTime")
	        .fixedInterval(DateHistogramInterval.DAY)
          .format("yyyy-MM-dd").timeZone(ZoneId.systemDefault()).minDocCount(1)
          //去重子桶
          .subAggregation(aggregationBuilder);
        NativeSearchQuery searchQuery = new NativeSearchQueryBuilder()
            .withQuery(boolQueryBuilder)
            .withPageable(PageRequest.of(0, 1))
            .addAggregation(aggs)
            .build();
 restTemplate.search(searchQuery, clockInPO.class)