2

我有以下格式的数据：

DATE                 DATA1                 DATA2
-------------------------------------------------
20121010             ABC                   DEF
20121010             DEF                   ABC
20121010             HIJ                   KLM
20121010             KLM                   HIJ
20121212             ABC                   DEF
20121212             DEF                   ABC
20121212             HIJ                   KLM
20121212             KLM                   HIJ

我想要做的是选择第 1 行和第 3 行。我不关心第 2 行和第 4 行，因为它们在我眼中本质上是“重复的”。

看起来很简单，但我只是想把查询放在一起来完成这个。

4

5 回答 5

1

row_number()假设您使用的是 2005 或更高版本，您可以使用该功能：

select date, data1, data2
from (select t.*,
             row_number() over (partition by date order by date) as seqnum
      from t
     ) t
where seqnum = 1

该表达式order by date应在任何支持row_number. 在 SQL Server 中，您还可以使用order by (select NULL).

或者，我意识到您的问题可能是关于消除重复的，无论顺序如何。为此，您可以这样做：

select distinct date, minData, maxData
from (select t.date,
             (case when data1 > data2 then data1 else data2 end) as minData,
             (case when data1 > data2 then data2 else data1 end) as maxData
      from t
     ) t

但是，当只出现一行时，这可能会重新排列这两个值。

保持列的原始顺序并消除额外行的更复杂的解决方案结合了两种方法：

select date, data1, data2
from (select t.*,
             row_number() over (partition by date order by minData, maxData) as seqnum
      from (select t.*
                   (case when data1 > data2 then data1 else data2 end) as minData,
                   (case when data1 > data2 then data2 else data1 end) as maxData
            from t
           ) t
     ) t
where seqnum = 1
于 2013-01-05T16:48:38.023 回答
1 
SELECT Date,  Data1, Data2
FROM tableX
WHERE Data1 <= Data2

UNION 

SELECT Date,  Data2, Data1
FROM tableX
WHERE Data2 < Data1 ;
于 2013-01-05T22:28:44.390 回答
0

我喜欢这样：但我相信如果你使用 preSQL-Server 2008R2

;WITH myCTE
        AS
        (
        SELECT 
            [Rw] = ROW_NUMBER() OVER (ORDER BY [Date]),
            [Date],
            [DATA1],
            [DATA2]
        FROM #data
        )
SELECT *
FROM myCTE x    
WHERE NOT EXISTS
            (
            SELECT 1
            FROM myCTE y
            WHERE
                x.DATA1 = y.DATA2 AND
                x.Rw > y.Rw AND
                x.Date = y.Date
            )

这是SQL Fiddle上的实时插图

于 2013-01-05T17:11:20.220 回答
0

你可以试试这个：

SQL 演示在这里

;WITH CTE AS
(
  SELECT date, data1, data2, 
  CASE WHEN DATA2 > DATA1 THEN data1 + data2 
  ELSE data2 + data1 END d
  FROM T
),CTE2 AS 
(
  SELECT *,
  ROW_NUMBER() OVER (PARTITION BY DATE, d 
                     ORDER BY data1) rn
  FROM CTE
)
SELECT date, data1, data2 FROM CTE2 WHERE rn = 1
于 2013-01-05T17:30:18.247 回答
0 
 ;WITH cte AS
 (
  SELECT DATE, DATA1, DATA2, ROW_NUMBER() OVER(ORDER BY DATE, DATA1) AS Id
  FROM dbo.test70 t
  )
  SELECT c.DATE, c.DATA1, c.DATA2
  FROM cte c LEFT JOIN cte ct ON c.Id = ct.Id + 1 AND c.DATA1 = ct.DATA2 
  WHERE ct.DATE IS NULL

SQLFiddle上的演示

于 2013-01-05T22:12:26.023 回答