SQL语句实现横排 2

前一篇文章 SQL语句实现横排 介绍了在SQL SERVER 2000中实现数据横排的功能,这篇介绍在最新的SQLSERVER 2005中的实现方法。


SQL SERVER 2005中新增加了两个关系运算符 PIVOT/ UNPIVOT,能够实现表中的列转换到行,以及行到列的转换工作。

举例,还是先创建测试数据表

CREATE   TABLE  sales.salesByMonth
(
year   char ( 4 ),
month   char ( 3 ),
amount 
money ,
PRIMARY   KEY  ( year month )
)

INSERT   INTO  sales.salesByMonth ( year month , amount)
VALUES ( ' 2004 ' , ' Jan ' 789.0000 )
INSERT   INTO  sales.salesByMonth ( year month , amount)
VALUES ( ' 2004 ' , ' Feb ' 389.0000 )
INSERT   INTO  sales.salesByMonth ( year month , amount)
VALUES ( ' 2004 ' , ' Mar ' 8867.0000 )
INSERT   INTO  sales.salesByMonth ( year month , amount)
VALUES ( ' 2004 ' , ' Apr ' 778.0000 )
INSERT   INTO  sales.salesByMonth ( year month , amount)
VALUES ( ' 2004 ' , ' May ' 78.0000 )
INSERT   INTO  sales.salesByMonth ( year month , amount)
VALUES ( ' 2004 ' , ' Jun ' 9.0000 )
INSERT   INTO  sales.salesByMonth ( year month , amount)
VALUES ( ' 2004 ' , ' Jul ' 987.0000 )
INSERT   INTO  sales.salesByMonth ( year month , amount)
VALUES ( ' 2004 ' , ' Aug ' 866.0000 )
INSERT   INTO  sales.salesByMonth ( year month , amount)
VALUES ( ' 2004 ' , ' Sep ' 7787.0000 )
INSERT   INTO  sales.salesByMonth ( year month , amount)
VALUES ( ' 2004 ' , ' Oct ' 85576.0000 )
INSERT   INTO  sales.salesByMonth ( year month , amount)
VALUES ( ' 2004 ' , ' Nov ' 855.0000 )
INSERT   INTO  sales.salesByMonth ( year month , amount)
VALUES ( ' 2004 ' , ' Dec ' 5878.0000 )
INSERT   INTO  sales.salesByMonth ( year month , amount)
VALUES ( ' 2005 ' , ' Jan ' 7.0000 )
INSERT   INTO  sales.salesByMonth ( year month , amount)
VALUES ( ' 2005 ' , ' Feb ' 6868.0000 )
INSERT   INTO  sales.salesByMonth ( year month , amount)
VALUES ( ' 2005 ' , ' Mar ' 688.0000 )
INSERT   INTO  sales.salesByMonth ( year month , amount)
VALUES ( ' 2005 ' , ' Apr ' 9897.0000 )

我们想要得到类似这样的结果:
Year  Jan            Feb             Mar       ..............
----- ---------- ----------- -----------
2004 789.0000 389.0000     8867.0000 .............
2005 7.0000     6868.0000   688.0000 ..............

上一篇文章介绍的方法当然可以实现,但现在这里想要的列是固定的,不是动态的,就是12个月,所以也可以这样子来用:
SELECT   year ,
SUM ( case   when   month   =   ' Jan '   then  amount  else   0   end AS   ' Jan ' ,
SUM ( case   when   month   =   ' Feb '   then  amount  else   0   end AS   ' Feb ' ,
SUM ( case   when   month   =   ' Mar '   then  amount  else   0   end AS   ' Mar ' ,
SUM ( case   when   month   =   ' Apr '   then  amount  else   0   end AS   ' Apr ' ,
SUM ( case   when   month   =   ' May '   then  amount  else   0   end AS   ' May ' ,
SUM ( case   when   month   =   ' Jun '   then  amount  else   0   end AS   ' Jun ' ,
SUM ( case   when   month   =   ' Jul '   then  amount  else   0   end AS   ' Jul ' ,
SUM ( case   when   month   =   ' Aug '   then  amount  else   0   end AS   ' Aug ' ,
SUM ( case   when   month   =   ' Sep '   then  amount  else   0   end AS   ' Sep ' ,
SUM ( case   when   month   =   ' Oct '   then  amount  else   0   end AS   ' Oct ' ,
SUM ( case   when   month   =   ' Nov '   then  amount  else   0   end AS   ' Nov ' ,
SUM ( case   when   month   =   ' Dec '   then  amount  else   0   end AS   ' Dec '
FROM  sales.salesByMonth
GROUP   by   year


但这样事实上还是相当麻烦的,现在SQLSERVER2005中有更方便的实现方法。
SELECT   Year , [ Jan ] , [ Feb ] , [ Mar ] , [ Apr ] , [ May ] , [ Jun ] , [ Jul ] , [ Aug ] , [ Sep ] , [ Oct ] , [ Nov ] , [ Dec ]
FROM  (
  
SELECT   year , amount,  month
  
FROM  sales.salesByMonth )  AS  salesByMonth
PIVOT ( 
SUM (amount)  FOR   month   IN
  (
[ Jan ] , [ Feb ] , [ Mar ] , [ Apr ] , [ May ] , [ Jun ] , [ Jul ] , [ Aug ] , [ Sep ] , [ Oct ] , [ Nov ] , [ Dec ] )
  ) 
AS  ourPivot
ORDER   BY   Year

就是这样,很简单的用法,效果是完全一样的。

我们再尝试一下把year去掉:
SELECT   [ Jan ] , [ Feb ] , [ Mar ] , [ Apr ] , [ May ] , [ Jun ] , [ Jul ] , [ Aug ] , [ Sep ] , [ Oct ] , [ Nov ] , [ Dec ]
FROM  (  SELECT  amount,  month
FROM  sales.salesByMonth )  AS  salesByMonth
PIVOT ( 
SUM (amount)  FOR   month   IN
(
[ Jan ] , [ Feb ] , [ Mar ] , [ Apr ] , [ May ] , [ Jun ] , [ Jul ] , [ Aug ] , [ Sep ] , [ Oct ] , [ Nov ] , [ Dec ] )
AS  ourPivot


得到的结果是:
Jan                 Feb                 Mar             ...
---------- ------------ -----------
796.0000     7257.0000     9555.0000     ...

同一个月份的数据累加到一起。


再给个微软官方的例子:
SQL语句实现横排 2_第1张图片



 

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