在sql中查找最常见的值并按从最高到最低的顺序排序(asc)

Question

我有一个简单的查询.

    select id, patient_id, diagnosis from dbo.diabetes_rx_tracker

group by id, patient_id, diagnosis

最常见的诊断代码需要显示在列表顶部并带有计数.

我尝试使用count函数.

但它将每个患者的所有值都返回为1而不是添加.

select id, patient_id, count(diagnosis) from dbo.diabetes_rx_tracker

group by id, patient_id, diagnosis

在编辑我的小组时,我也一直在抛出错误.

任何帮助将不胜感激.谢谢.

Answer 1

这看起来像你没有足够的聚合.GROUP by中的每个字段代表一个总计与其他字段聚合的字段.所以这只会通过id,病人和诊断向你展示诊断.不是很有帮助.

要获得最常见的诊断期,请从分组中删除id和patient_id:

select
  count(diagnosis)
from dbo.diabetes_rx_tracker 
group by 
  diagnosis 
order by 
  count(diagnosis) desc

要获取所有ID中最常见的代码,请从分组中删除patient_id并选择:

select
  diagnosis, 
  id, 
  count(1) as CodeCount 
from dbo.diabetes_rx_tracker 
group by 
  diagnosis, 
  id 
order by 
  count(diagnosis) desc

更新:根据您的新标准,这是您想要的.

select 
  id, 
  diagnosis, 
  ct 
from (
    select 
      row_number() OVER (PARTITION BY id ORDER BY count(diagnosis) desc ) as rn, 
      count(diagnosis) as ct, 
      diagnosis, 
      id
    from dbo.diabetes_rx_tracker 
    group by 
      id, 
      diagnosis
    ) ranked
where 
  rn = 1
order by
  CT desc