使用Oracle操作xml格式数据的方法

-- Create table
create table XMLTEST
(
  id      NUMBER,
  content VARCHAR2(4000)
);

insert into XMLTEST (id, content)
values (1, '<root><app><id>1</id><name>张三</name><age>18</age></app><app><id>2</id><name>李四</name><age>20</age></app><app><id>3</id><name>王五</name><age>30</age></app></root>');
insert into XMLTEST (id, content)
values (2, '<root><app><id>1</id><name>张三</name><age>18</age></app></root>');

--extract 返回一个节点下的所有值
select  extract(xmltype(CONTENT), 'root/app/name') vxml from xmltest where id = 1;

--extractvalue只能返回一个节点的一个值  
select x.id tblid,
extractvalue(xmltype(x.CONTENT),'root/app/id') as id,
extractvalue(xmltype(x.CONTENT),'root/app/name') as name,
extractvalue(xmltype(x.CONTENT),'root/app/age') as age
from xmltest x where x.id = 2;

--table和XMLSequence 将xml节点数据转为表数据格式
select  x.id tblid,
extractValue(value(newval),'/app/id') id,
extractValue(value(newval),'/app/name') name,
extractValue(value(newval),'/app/age') name
from xmltest x,
table(XMLSequence( extract(xmltype(x.CONTENT), 'root/app') )) newval
where x.id = 1;