Question

这是我的查询

  SELECT
    client_id,
   TimesTested,
    CAST(COUNT(*) AS varchar(30)) AS count,
    CAST(AVG(testfreq) as varchar(30)) as TestFreq,
    CAST(STDEV(TestFreq) as varchar(30)) Stdv
  FROM counted
  GROUP BY
    client_id,
    TimesTested

有效;但是，我需要过滤AVG和STDEV，其中testfreq> 0但我需要计数（*）不要过滤。

最接近的是：

  SELECT
    client_id,
   TimesTested,
    CAST(COUNT(*) AS varchar(30)) AS count,
    CAST(AVG(testfreq) as varchar(30)) as TestFreq,
    CAST(STDEV(TestFreq) as varchar(30)) Stdv
  FROM counted
  where testfreq>0  --however I don't want this filtered applied to count(*)
  GROUP BY
    client_id,
    TimesTested

非常感谢你的指导！

Answer 1

您应该能够在聚合中使用CASE语句，类似于：

SELECT client_id,
   TimesTested,
   CAST(COUNT(*) AS varchar(30)) AS count,
   CAST(AVG(case when testfreq>0 then testfreq end) as varchar(30)) as TestFreq,
   CAST(STDEV(case when testfreq>0 then TestFreq end) as varchar(30)) Stdv
FROM counted
GROUP BY client_id,  TimesTested

我不确定为什么你需要这些作为varchars，是否有理由需要将这些值转换为varchar？

我只是按原样保留值：

SELECT client_id,
   TimesTested,
   COUNT(*) AS count,
   AVG(case when testfreq>0 then testfreq end) as TestFreq,
   STDEV(case when testfreq>0 then TestFreq end) Stdv
FROM counted
GROUP BY client_id,  TimesTested

在同一查询中的不同过滤器上选择聚合

1 个答案: