这个格式怎么实现?

Question

将sql语句a转换成b格式:
a:
year       quarter           amount
--------------------------------------------------
2000       1                 1.1
2000       2                 1.2
2000       3                 1.3
2000       4                 1.4
2001       1                 2.1
2001       2                 2.2
2001       3                 2.3
2001       4                 2.4b:
year      quarter 1     quarter 2     quarter 3    quarter 4
2000      1.1            1.2            1.3         1.4
2001      2.1            2.2            2.3         2.4

Answer 1

如果quarter只有四个值可以这样：
select year,
sum(decode(quarter,1,amount,0)) quarter1,
sum(decode(quarter,2,amount,0)) quarter2,
sum(decode(quarter,3,amount,0)) quarter3,
sum(decode(quarter,4,amount,0)) quarter4
from table
group by year

Answer 2

select year,
sum(decode(quarter,1,amount,0)) quarter1,
sum(decode(quarter,2,amount,0)) quarter2,
sum(decode(quarter,3,amount,0)) quarter3,
sum(decode(quarter,4,amount,0)) quarter4
from table
group by year
固定的情况用这种，否则要用动态sql

Answer 3

有个SQL语句可以转换的，找一下吧，另外列不固定难度比较大