求一SQL語句 - MS-SQL Server / 基础类

SQL code:

--表結構
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[tTable]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
drop table [dbo].[tTable]
GO

CREATE TABLE [dbo].[tTable] (
[fPFgCode] [varchar] (30) COLLATE Chinese_Taiwan_Stroke_CI_AS NOT NULL ,
[fFgCode] [varchar] (30) COLLATE Chinese_Taiwan_Stroke_CI_AS NOT NULL ,
[fup] [decimal](18, 2) NULL
) ON [PRIMARY]
GO

ALTER TABLE [dbo].[tTable] WITH NOCHECK ADD
CONSTRAINT [PK_tTable] PRIMARY KEY CLUSTERED
(
[fPFgCode],
[fFgCode]
) ON [PRIMARY]
GO



數據
fPfgCode fFgCode fup
A PA 100.00
A PB NULL
A PC 200.00
B PB NULL
B PC 200.00
C PA 100.00
C PC 200.00

結果
fPfgCode fFgCode
也就是以fPfgCode分組，當組有任一條記錄的fup為null,則此fPfgCode之和為0,否則為SUM之和

要求：
1.一條SQL語句實現
2.不能用子查詢




A 0
B 0
C 300

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結果怎麼跑位了
fPfgCode fFgCode
A 0
B 0
C 300

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SQL code:
select distinct fPfgCode,isnull(fup,0