在前面的文章https://blog.csdn.net/post_yuan/article/details/54845987中，我们介绍了Trafodion的group_concat函数，可以用于把多列转成一行（根据某种分隔符）。
本文我们介绍另一函数PIVOT，PIVOT是另一个行列转换的利器。以下我们简单模拟使用PIVOT的例子，
首先，创建测试表并插入测试数据，
CREATE TABLE salesorder
(
shop VARCHAR(50),
product VARCHAR(50),
account BIGINT
);
INSERT INTO salesorder
SELECT 'ShopA','A',round(100+100*rand(),0) FROM DUAL UNION ALL
SELECT 'ShopA','A',round(100+100*rand(),0) FROM DUAL UNION ALL
SELECT 'ShopA','B',round(200+100*rand(),0) FROM DUAL UNION ALL
SELECT 'ShopA','B',round(200+100*rand(),0) FROM DUAL UNION ALL
SELECT 'ShopA','B',round(200+100*rand(),0) FROM DUAL UNION ALL
SELECT 'ShopA','C',round(1000+100*rand(),0)FROM DUAL UNION ALL
SELECT 'ShopB','A',round(100+100*rand(),0) FROM DUAL UNION ALL
SELECT 'ShopB','A',round(100+100*rand(),0) FROM DUAL UNION ALL
SELECT 'ShopB','B',round(200+100*rand(),0) FROM DUAL UNION ALL
SELECT 'ShopB','C',round(1000+100*rand(),0)FROM DUAL UNION ALL
SELECT 'ShopB','C',round(1000+100*rand(),0)FROM DUAL UNION ALL
SELECT 'ShopC','A',round(100+100*rand(),0) FROM DUAL UNION ALL
SELECT 'ShopC','B',round(200+100*rand(),0) FROM DUAL UNION ALL
SELECT 'ShopC','B',round(200+100*rand(),0) FROM DUAL UNION ALL
SELECT 'ShopC','B',round(200+100*rand(),0) FROM DUAL UNION ALL
SELECT 'ShopC','B',round(200+100*rand(),0) FROM DUAL UNION ALL
SELECT 'ShopC','C',round(1000+100*rand(),0)FROM DUAL UNION ALL
SELECT 'ShopC','C',round(1000+100*rand(),0)FROM DUAL ;查询表数据，数据成功插入，
SQL>SELECT * FROM salesorder;
SHOP PRODUCT ACCOUNT
-------------------------------------------------- -------------------------------------------------- --------------------
ShopC C 125725026600
ShopC C 125807380900
ShopC B 175364500300
ShopC B 206319632900
ShopC B 210124737700
ShopC B 126031200
ShopC A 3497515300
ShopB C 6801772400
ShopB C 10611919300
ShopB B 14312819900
ShopB A 18480955800
ShopB A 21334784400
ShopA C 24344919000
ShopA B 27237402900
ShopA B 30129887600
ShopA B 32928253100
ShopA A 35958555100
ShopA A 36029144500现在我们尝试使用PIVOT函数来查询shop为ShopA的product的值有哪些，
SQL>SELECT PIVOT(product) FROM salesorder WHERE shop = 'ShopA';
(EXPR)
--------------------------------------------------------------------------------------------------------------------------------
C,B,B,B,A,A
--- 1 row(s) selected.
SQL>SELECT shop,PIVOT(product) as product FROM salesorder WHERE shop = 'ShopA' group by shop;
SHOP PRODUCT
-------------------------------------------------- --------------------------------------------------------------------------------------------------------------------------------
ShopA B,B,B,A,A,C
--- 1 row(s) selected.可以看出，PIVOT十分的好用，PIVOT属于聚合函数，类似于COUNT、SUM、AVG这种，只不过它是把函数中的值做了拼接，默认以逗号分隔。下面这条语句指定分隔符输出，
SQL>SELECT shop,PIVOT(product, delimiter '-') as product FROM salesorder WHERE shop = 'ShopA' group by shop;
SHOP PRODUCT
-------------------------------------------------- --------------------------------------------------------------------------------------------------------------------------------
ShopA B-B-B-A-A-C
--- 1 row(s) selected.