Restrict Query Resultset which uses Analytic Function

Question

Gents,
Problem Definition: Using Analytic Function, get Total sales for the Product P1
and Customer C1 [Total sales for the customer itself] in one line.
I want to restrict the ResultSet of the query to Product P1,
please look at the data below, queries and problems..
Data
Customer Product Qtr Sales
C1 P1 19991 100.00
C1 P1 19992 125.00
C1 P1 19993 175.00
C1 P1 19994 300.00
C1 P2 19991 100.00
C1 P2 19992 125.00
C1 P2 19993 175.00
C1 P2 19994 300.00
C2 P1 19991 100.00
C2 P1 19992 125.00
C2 P1 19993 175.00
C2 P1 19994 300.00
Problem, I want to display....
Customer Product ProdSales CustSales
C1 P1 700 1400
But Without using outer query, i.e. please look below for the query that
returns this reult with two select, I want this result in one query only..
Select * From ----*** want to avoid this... ***----
(Select Customer,Product,
Sum(Sales) ProdSales,
Sum(Sum(Sales)) Over(Partition By Customer) CustSales
From t1
Where customer='C1')
Where
Product='P1' ;
Also, I want to avoid Hard coding of P1 in the select clause....
I mean, I can do it in one shot/select, but look at the query below, it uses
P1 in the select clause, which is No No!! P1 is allowed only in Where or Having ..
Select Customer,Decode(Product, 'P1','P1','P1') Product,
Decode(Product,'P1',Sales,0) ProdSales,
Sum(Sum(Sales)) Over (Partition By Customer ) CustSales
From t1
Where customer='C1' ;
This will get me what I want, but as I said earlier, I want to avoid using P1 in the
Select clause..
Goal is to Avoid using
1-> Two Select/Outer Query/In Line Views
2-> Product 'P1' in the Select clause...
Thanks
-Dhaval Rasania

Answer 1

I don't understand goal number 1 of not using an inline view.
What is the harm?