Question

给出以下表格结构

Col1, Col2, EventType,  DateTime

如何选择Col1，Col2的每个分组记录，该记录位于EventType = 3 Col1特定组Col2的最高记录之后}。

例如，包含以下数据

Col1, Col2, EventType, DateTime
A       B       1      2012-1-1
A       B       3      2011-1-1
A       B       1      2010-1-1
C       D       1      2012-1-1
C       D       2      2011-1-1
C       D       2      2010-1-1
C       D       3      2009-1-1
C       D       2      2008-1-1
C       D       3      2007-1-1
C       D       1      2006-1-1
C       D       2      2005-1-1

我想选择

Col1, Col2, EventType, DateTime
A       B       1      2012-1-1

C       D       1      2012-1-1
C       D       2      2011-1-1
C       D       2      2010-1-1

Answer 1

您可以在子查询上使用max函数：

SELECT Col1, Col2, EventType, DateTime 
FROM theTable A
WHERE DateTime > 

(SELECT  MAX(DateTime)
FROM    theTable SUB
WHERE   EventType = 3
AND SUB.COL1 = A.COL1
AND SUB.COL2 = A.COL2)

Answer 2

可以使用ROW_NUMBER()来解决此问题：

将行分为(Col1, Col2)组，并按DateTime的升序对每个组中的行进行排名。

Col1  Col2  EventType  DateTime  EventRank
----  ----  ---------  --------  ---------
A     B     1          2012-1-1  3
A     B     3          2011-1-1  2
A     B     1          2010-1-1  1
C     D     1          2012-1-1  8
C     D     2          2011-1-1  7
C     D     2          2010-1-1  6
C     D     3          2009-1-1  5
C     D     2          2008-1-1  4
C     D     3          2007-1-1  3
C     D     1          2006-1-1  2
C     D     2          2005-1-1  1

此外，按(Col1, Col2, EventType)对行进行分区，并按DateTime的降序顺序对其进行排名。

Col1  Col2  EventType  DateTime  EventRank  EventSubRank
----  ----  ---------  --------  ---------  ------------
A     B     1          2012-1-1  3          1
A     B     3          2011-1-1  2          1
A     B     1          2010-1-1  1          2
C     D     1          2012-1-1  8          1
C     D     2          2011-1-1  7          1
C     D     2          2010-1-1  6          2
C     D     3          2009-1-1  5          1
C     D     2          2008-1-1  4          3
C     D     3          2007-1-1  3          2
C     D     1          2006-1-1  2          2
C     D     2          2005-1-1  1          4

选择EventType = 3 AND EventSubRank = 1。

的子集

Col1  Col2  EventType  DateTime  EventRank  EventSubRank
----  ----  ---------  --------  ---------  ------------
A     B     3          2011-1-1  2          1
C     D     3          2009-1-1  5          1

将其作为过滤器使用，将其连接回排名的行集，并选择后者的行EventRank值大于子集中的相应值。

这是一个完整的查询：

WITH ranked AS (
  SELECT
    *,
    EventRank    = ROW_NUMBER() OVER (PARTITION BY Col1, Col2            ORDER BY DateTime ASC ),
    EventSubRank = ROW_NUMBER() OVER (PARTITION BY Col1, Col2, EventType ORDER BY DateTime DESC)
  FROM atable
),
filtered AS (
  SELECT *
  FROM ranked
  WHERE EventType    = 3
    AND EventSubRank = 1
)
SELECT
  r.Col1,
  r.Col2,
  r.EventType,
  r.DateTime
FROM ranked
INNER JOIN filtered f
   ON r.Col1 = f.Col1
  AND r.col2 = f.Col2
  AND r.EventRank > f.EventRank
;

Answer 3

select Col1, Col2, EventType, DateTime 
From yourtable A, 
(select Col1, Col2 from yourtable  group by Col1, Col2) B 
where A.EventType<3 and A.Col1 =B.Col1 And A.Col2=B.Col2

Answer 4

获得预期结果

       Select   Col1, Col2, EventType, DateTime  from table where EventType<3

Answer 5

试试这个，

Select a.* FROm yourtable A JOIN

(SELECT * FROM yourTable WHERE EventType=3) b
ON A.Col1=B.Col1
AND A.Col2 = B.Col2
WHERE A.dateTime>B.DateTime

如何在sql中的组内的某个记录之后选择所有记录？

5 个答案: