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一个纠结了许久的有关问题,让小弟我头晕的Group By。%¥#&×&@~

热度:242   发布时间:2016-04-27 11:02:59.0
一个纠结了许久的问题,让我头晕的Group By。。%¥#&×&@~~
客户名称,日期,产品,单价,备注
Cus Date Caption Price Memo
A 2012-02-26 K1 18 A1
A 2012-04-15 K2 19 A2
B 2012-01-13 K1 18 A3
B 2012-02-27 K1 18 A4
B 2012-05-06 K1 18 A5
B 2012-05-07 K1 18.5 A6
B 2012-01-13 K2 20 A7
B 2012-05-16 K2 19.5 A8
B 2012-05-30 K2 19.5 A9
B 2012-08-15 K2 19.5 A10
C 2012-01-17 K3 25 A11
C 2012-03-12 K3 25 A12
C 2012-04-17 K3 25 A13
C 2012-05-18 K3 26 A14
C 2012-02-15 K1 18 A15
C 2012-07-09 K2 19 A16
C 2012-05-13 K5 22 A17
C 2012-03-04 K4 10 A18
C 2012-05-13 K4 11 A19
C 2012-05-14 K4 11 A20

----上面一组数据,要输出为:

客户名称,日期,产品,单价,备注
Cus Date Caption Price Memo
A 2012-02-26 K1 18 A1
A 2012-04-15 K2 19 A2
B 2012-05-07 K1 18.5 A6
B 2012-08-15 K2 19.5 A10
C 2012-05-18 K3 26 A14
C 2012-02-15 K1 18 A15
C 2012-07-09 K2 19 A16
C 2012-05-13 K5 22 A17
C 2012-05-14 K4 11 A20

-----------------凌乱的分割线---------------
实际上是这个意思:
我想列出客户、产品和最近一次价格的数据,类似于价格表,要过滤掉无用的数据,只保留最新数据。
可是问题在于如果将Price字段进行GroupBy,则无法去掉无用数据。
如果不进行groupBy则需要用聚合函数,Price字段一操作聚合函数就不是我想要的数据了。

不知道有没有办法不用聚合函数,或者其他什么办法保留原数据,并且还能GroupBy其他字段数据?



------解决方案--------------------
试试是不是你想要的:
SQL code
WITH test (Cus,    [Date],     Caption,    Price    ,Memo) AS  ( SELECT 'A'    ,'2012-02-26'    ,'K1',    18    ,'A1'  union all  SELECT 'A',    '2012-04-15',    'K2',    19    ,'A2'  union all  SELECT 'B',    '2012-01-13',    'K1',    18    ,'A3'  union all  SELECT 'B'    ,'2012-02-27',    'K1',    18    ,'A4'  union all  SELECT 'B'    ,'2012-05-06',    'K1',    18    ,'A5'  union all  SELECT 'B'    ,'2012-05-07',    'K1',    18.5    ,'A6'  union all  SELECT 'B',    '2012-01-13',    'K2',    20    ,'A7'  union all  SELECT 'B',    '2012-05-16',    'K2',    19.5    ,'A8'  union all  SELECT 'B',    '2012-05-30',    'K2',    19.5    ,'A9'  union all  SELECT 'B',    '2012-08-15',    'K2',    19.5    ,'A10'  union all  SELECT 'C',    '2012-01-17',    'K3',25    ,'A11'  union all  SELECT 'C',    '2012-03-12',    'K3',    25    ,'A12'  union all  SELECT 'C',    '2012-04-17',    'K3',    25    ,'A13'  union all  SELECT 'C',    '2012-05-18',    'K3',    26    ,'A14'  union all  SELECT 'C',    '2012-02-15',    'K1',    18    ,'A15'  union all  SELECT 'C',    '2012-07-09',    'K2',    19    ,'A16'  union all  SELECT 'C',    '2012-05-13',    'K5',    22    ,'A17'  union all  SELECT 'C',    '2012-03-04',    'K4',    10    ,'A18'  union all  SELECT 'C',    '2012-05-13',    'K4',    11    ,'A19'   union all  SELECT 'C',    '2012-05-14',    'K4',    11    ,'A20' ) SELECT * FROM  test a WHERE EXISTS (SELECT 1 FROM ( SELECT cus,MAX([date])[date] ,Caption FROM test  GROUP BY cus,Caption) b WHERE a.cus=b.cus AND a.[date]=b.[date] AND a.Caption=b.Caption)  /* Cus  Date       Caption Price                                   Memo ---- ---------- ------- --------------------------------------- ---- A    2012-02-26 K1      18.0                                    A1 A    2012-04-15 K2      19.0                                    A2 B    2012-05-07 K1      18.5                                    A6 B    2012-08-15 K2      19.5                                    A10 C    2012-05-18 K3      26.0                                    A14 C    2012-02-15 K1      18.0                                    A15 C    2012-07-09 K2      19.0                                    A16 C    2012-05-13 K5      22.0                                    A17 C    2012-05-14 K4      11.0                                    A20  (9 行受影响)  */
------解决方案--------------------
SQL code
 SELECT *  FROM test AS t1 WHERE NOT EXISTS(SELECT 1 FROM Test AS t2 WHERE t1.cus = t2.cus AND t1.caption = t2.caption AND t1.date < t2.date)
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