如何選擇未超過值的記錄

Question

我希望從數據庫中提取一份工作ID列表，其中每個工作的狀態未超過給定條件。

對於此示例表，我想顯示所有未超過狀態200的Jobid，並僅顯示最新狀態。

作業進度表

Jobid Status Date      Time
1234  100    20131001  080000
1234  200    20131001  100000
1234  300    20131001  140000
9876  100    20131014  110000
5555  100    20131015  100000
5555  200    20131016  080000

我正在尋找的結果是

Jobid Status Date      Time
9876  100    20131014  110000
5555  200    20131016  080000

數據庫在AS400上

Answer 1

這是窗口/分析功能的良好用法。

您可以使用row_number()獲取最新狀態。 您可以使用sum() over來計算狀態超過200的次數。

select jobid, Status, Date, Time
from (select jp.*,
             row_number() over (partition by jobid order by date desc, time desc) as seqnum,
             sum(case when status >= 200 then 1 else 0 end) over (partition by jobid) as status_200
      from JobProgress jp
     ) jp
where status_200 = 0 and seqnum = 1;

然后where子句將過濾到要查找的行。

Answer 2

select t1.* 
from your_table t1
inner join 
(
  select Jobid, max(date*1000000+time) as maxdt
  from your_table
  group by jobid
  having sum(case when status > 200 then 1 else 0 end) = 0
) t2 on t1.jobid = t2.jobid 
     and t1.date*100000+t1.time = maxdt

Answer 3

在SQL Server中，您可以使用ROW_NUMBER ：

SELECT *
FROM (SELECT
            Jobid,
            status,
            ROW_NUMBER() OVER(PARTITION BY Jobid ORDER BY Date DESC) AS rn
      FROM
            Job-Progress
      WHERE Status < 200) A
WHERE RowNum = 1

Answer 4

這是我能想到的最簡單的方法：

SELECT t.* FROM t
INNER JOIN (
  SELECT jobid, max(date) date FROM t
  GROUP BY jobid
  HAVING COUNT(CASE WHEN status > 200 THEN 1 END) = 0
) s
ON t.jobid = s.jobid AND t.date = s.date

在這里擺弄。

Answer 5

一個通用的表表達式將允許您使用ROW_NUMBER（）函數將每個作業的最新行標記為1。然后，您所要做的就是在狀態允許的情況下選擇該行。

With x as
(SELECT *,
        ROW_NUMBER() OVER(PARTITION BY Jobid ORDER BY Date, time DESC) AS pick
      FROM JobProgress
)
SELECT jobid, status, date, time
  FROM x
  WHERE Status <= 200
    And pick = 1