SQL Server 行轉列和列轉行

說在前面

做一個數據統計和分析的項目，每天面對著各種數據，經過存儲過程從源表計算匯總后需要寫入中間結果表以提高數據使用效率，那么此時就需要用到行轉列和列轉行。

1、列轉行

數據經過計算加工后會直接生成前端圖表需要的數據源，但是程序里又需要把該數據經過列轉行寫入中間表中，下次再查詢該數據時直接從中間表查詢數據。

1.1 列換行語法

table_source

UNPIVOT(

value_column

FOR pivot_column

IN(<column_list>)

)

1.2  行轉列案例

WITH T
AS
(
  SELECT 1 as TeamId,'測試團隊1' as Team,80 'MEN',20 'WOMEN'
  UNION 
  SELECT 2 as TeamId,'測試團隊2' as Team,30 'MEN',70 'WOMEN' 
)
---列轉行------------------------------------
SELECT TeamId,Team ,TYPE=ATTRIBUTE,CNT=VALUE
FROM T 
UNPIVOT (
  VALUE FOR ATTRIBUTE IN ([MEN],[WOMEN])
) AS UPV

2、 行轉列

行轉列主要是從中間表里查詢數據，SQL SERVER2005以下的版本則可以使用聚合函數來完成。

2.1 行轉列語法

table_source

PIVOT(

聚合函數（value_column）

FOR pivot_column

IN(<column_list>)

)

2.2、使用PIVOT實現

WITH T
AS
(
  SELECT  1 AS ID,'測試團隊1' TEAM,'MEN' ITEM,80 CENT
  UNION
  SELECT  1 AS ID,'測試團隊1' TEAM,'WOMEN' ITEM,20 CENT
  UNION
  SELECT  2 AS ID,'測試團隊2' TEAM,'MEN' ITEM,30 CENT
  UNION
  SELECT  2 AS ID,'測試團隊2' TEAM,'WOMEN' ITEM,70 CENT
)

SELECT * FROM T PIVOT (SUM(CENT) FOR ITEM IN ([MEN],[WOMEN])) A

2.3、使用聚合函數實現

WITH T
AS
(
  SELECT  1 AS ID,'測試團隊1' TEAM,'MEN' ITEM,80 CENT
  UNION
  SELECT  1 AS ID,'測試團隊1' TEAM,'WOMEN' ITEM,20 CENT
  UNION
  SELECT  2 AS ID,'測試團隊2' TEAM,'MEN' ITEM,30 CENT
  UNION
  SELECT  2 AS ID,'測試團隊2' TEAM,'WOMEN' ITEM,70 CENT
)

SELECT ID,TEAM,
SUM(CASE WHEN ITEM='MEN' THEN CENT ELSE 0 END) 'MEN',
SUM(CASE WHEN ITEM='WOMEN' THEN CENT ELSE 0 END) 'WOMEN' 
FROM T
GROUP BY ID,TEAM

參考資料

http://www.cnblogs.com/zhangzt/archive/2010/07/29/1787825.html

http://www.cnblogs.com/aspnethot/articles/1762665.html