求SQL语句，两条记录合并
TABLE：   TA
fid     fqty       fgood_flag
1           20           Y  
1           30           N  
2           40           Y
2           50           N

合并为
fid       fgood     ffail
1             20         30
2             40         50


请问这样的语句该怎么写？

------解决方案--------------------
create table ta(fid varchar2(10),fqty integer, fgood_flag varchar2(1));
insert into ta
select 1,20, 'Y ' from dual
union all
select 1,30, 'N ' from dual
union all
select 2,40, 'Y ' from dual
union all
select 2,50, 'N ' from dual
//////////
select fid,sum(t.fgood) fgood ,sum(t.ffail) ffail
from(
select fid,sum(decode(fgood_flag, 'Y ',fqty)) fgood ,sum(decode(fgood_flag, 'N ',fqty)) ffail
from ta group by fid,fgood_flag
)t
group by fid
/////////输出结果
1 20 30
2 40 50
------解决方案--------------------
CREATE TABLE TA(fid VARCHAR2(2),fqty INTEGER,fgood_flag VARCHAR2(2));
INSERT INTO TA VALUES( '1 ',20, 'Y ');
INSERT INTO TA VALUES( '1 ',30, 'N ');
INSERT INTO TA VALUES( '2 ',40, 'Y ');
INSERT INTO TA VALUES( '2 ',50, 'N ');
INSERT INTO TA VALUES( '3 ',50, 'N ');
INSERT INTO TA VALUES( '4 ',40, 'Y ');
COMMIT;

SELECT T1.fid,fgood,ffail FROM(
SELECT fid,fqty fgood FROM TA WHERE fgood_flag= 'Y ')T1,
(SELECT fid,fqty ffail FROM TA WHERE fgood_flag= 'N ')T2
WHERE T1.fid=T2.fid(+)
UNION
SELECT T2.fid,fgood,ffail FROM(
SELECT fid,fqty fgood FROM TA WHERE fgood_flag= 'Y ')T1,
(SELECT fid,fqty ffail FROM TA WHERE fgood_flag= 'N ')T2
WHERE T2.fid=T1.fid(+);
如果fgood_flag是有一个N就有一个Y的话,就不用UNION了,用上面的语句就好,也不用外连.
写的语句太长了,等高手写好的方法吧.