Oracle 10g 行列转换(从SQL Server 2000迁移)

Oracle 10g 和SQL Server 2000还没有提供专门的行列转换函数，而SQL Server 2005和Oracle 11g都可以直接用PIVOT/UNPIVOT进行方便的转换。
当时看过SQL Server 2005 Inside T SQL Querying那本书，里面讲到SQL Server 2005及以前的版本中如何实现行列转行，原书的代码如下：

-- Listing 6-4: Creating and Populating the Orders Table

2USE tempdb;

3GO

4IF OBJECT_ID('dbo.Orders') IS NOT NULL

5 DROP TABLE dbo.Orders;

6GO

7CREATE TABLE dbo.Orders

8(

9 orderid int NOT NULL PRIMARY KEY NONCLUSTERED,

10 orderdate datetime NOT NULL,

11 empid int NOT NULL,

12 custid varchar(5) NOT NULL,

13 qty int NOT NULL

14);

15CREATE UNIQUE CLUSTERED INDEX idx_orderdate_orderid

16 ON dbo.Orders(orderdate, orderid);

17INSERT INTO dbo.Orders(orderid, orderdate, empid, custid, qty)

18 VALUES(30001, '20020802', 3, 'A', 10);

19INSERT INTO dbo.Orders(orderid, orderdate, empid, custid, qty)

20 VALUES(10001, '20021224', 1, 'A', 12);

21INSERT INTO dbo.Orders(orderid, orderdate, empid, custid, qty)

22 VALUES(10005, '20021224', 1, 'B', 20);

23INSERT INTO dbo.Orders(orderid, orderdate, empid, custid, qty)

24 VALUES(40001, '20030109', 4, 'A', 40);

25INSERT INTO dbo.Orders(orderid, orderdate, empid, custid, qty)

26 VALUES(10006, '20030118', 1, 'C', 14);

27INSERT INTO dbo.Orders(orderid, orderdate, empid, custid, qty)

28 VALUES(20001, '20030212', 2, 'B', 12);

29INSERT INTO dbo.Orders(orderid, orderdate, empid, custid, qty)

30 VALUES(40005, '20040212', 4, 'A', 10);

31INSERT INTO dbo.Orders(orderid, orderdate, empid, custid, qty)

32 VALUES(20002, '20040216', 2, 'C', 20);

33INSERT INTO dbo.Orders(orderid, orderdate, empid, custid, qty)

34 VALUES(30003, '20040418', 3, 'B', 15);

35INSERT INTO dbo.Orders(orderid, orderdate, empid, custid, qty)

36 VALUES(30004, '20020418', 3, 'C', 22);

37INSERT INTO dbo.Orders(orderid, orderdate, empid, custid, qty)

38 VALUES(30007, '20020907', 3, 'D', 30);

39GO

40-- Aggregating Data, Pre-2005 Solution, Total Qty

41SELECT custid,

42 SUM(CASE WHEN orderyear = 2002 THEN qty END) AS [2002],

43 SUM(CASE WHEN orderyear = 2003 THEN qty END) AS [2003],

44 SUM(CASE WHEN orderyear = 2004 THEN qty END) AS [2004]

45FROM (SELECT custid, YEAR(orderdate) AS orderyear, qty

46 FROM dbo.Orders) AS D

47GROUP BY custid;

48GO

49

本人照葫芦画瓢，将上面的代码迁移到Oracle 10g中，代码如下：

CREATE TABLE Orders

2(

3 orderid int NOT NULL PRIMARY KEY ,

4 orderdate date NOT NULL,

5 empid int NOT NULL,

6 custid varchar2(5) NOT NULL,

7 qty int NOT NULL

8);

9

10INSERT INTO Orders

11 (orderid, orderdate, empid, custid, qty)

12VALUES

13 (10001, to_date('20021224', 'yyyymmdd'), 1, 'A', 12);

14INSERT INTO Orders

15 (orderid, orderdate, empid, custid, qty)

16VALUES

17 (10005, to_date('20021224', 'yyyymmdd'), 1, 'B', 20);

18INSERT INTO Orders

19 (orderid, orderdate, empid, custid, qty)

20VALUES

21 (40001, to_date('20030109', 'yyyymmdd'), 4, 'A', 40);

22INSERT INTO Orders

23 (orderid, orderdate, empid, custid, qty)

24VALUES

25 (10006, to_date('20030118', 'yyyymmdd'), 1, 'C', 14);

26INSERT INTO Orders

27 (orderid, orderdate, empid, custid, qty)

28VALUES

29 (20001, to_date('20030212', 'yyyymmdd'), 2, 'B', 12);

30INSERT INTO Orders

31 (orderid, orderdate, empid, custid, qty)

32VALUES

33 (40005, to_date('20040212', 'yyyymmdd'), 4, 'A', 10);

34INSERT INTO Orders

35 (orderid, orderdate, empid, custid, qty)

36VALUES

37 (20002, to_date('20040216', 'yyyymmdd'), 2, 'C', 20);

38INSERT INTO Orders

39 (orderid, orderdate, empid, custid, qty)

40VALUES

41 (30003, to_date('20040418', 'yyyymmdd'), 3, 'B', 15);

42INSERT INTO Orders

43 (orderid, orderdate, empid, custid, qty)

44VALUES

45 (30004, to_date('20020418', 'yyyymmdd'), 3, 'C', 22);

46INSERT INTO Orders

47 (orderid, orderdate, empid, custid, qty)

48VALUES

49 (30007, to_date('20020907', 'yyyymmdd'), 3, 'D', 30);

50

51SELECT custid,

52 SUM(CASE WHEN orderyear = '2002' THEN qty END) as 二零零二,

53 SUM(CASE WHEN orderyear = '2003' THEN qty END)as 二零零三,

54 SUM(CASE WHEN orderyear = '2004' THEN qty END)as 二零零四

55FROM (SELECT custid, to_char(orderdate,'yyyy')AS orderyear, qty

56 FROM Orders) D

57GROUP BY custid;

算是一种行列转行的方案吧，O(∩_∩)O~