行转列的例子

一个群友的提问：

转换成

 create table htol (name varchar2(20),year varchar2(20));

 insert into htol values('A','2012');

--执行三次

insert into htol values('B','2012');

--执行五次

insert into htol values('A','2010');

--执行三次

insert into htol values('B','2010');

--执行两次

SQL> select * from htol;

NAME                 YEAR
-------------------- --------------------
A                    2012
A                    2012
A                    2012
B                    2012
B                    2012
B                    2012
B                    2012
B                    2012
A                    2010
A                    2010
A                    2010

NAME                 YEAR
-------------------- --------------------
B                    2010
B                    2010

已选择13行。

SQL> select year,decode(name,'A',total) name_a,decode(name,'B',total) name_b

from (select year,name,count(*) total from htol group by year,name) ;

YEAR                     NAME_A     NAME_B
-------------------- ---------- ----------
2010                          3
2012                                     5
2010                                     2
2012                          3
还有更好的方法实现图二的显示结果吗？