Really weird problem in Oracle

Question

Hey,
I am using Oracle 11g (11.1.0.6.0)
I am having this view, called "vw_sales".
The definition is as below :-
select a.pr_id, a.tm_id, a.cust_id, sum(a.inv_value*b.cu_factor*c.nt_factor) inv_value
from sales a, adc_rate b, uknt_rate c
where a.pr_id = b.pr_id
and a.tm_id = b.tm_id
and b.stpi_id = c.stpi_id
group by a.pr_id, a.tm_id, a.cust_id -- Query 2
Now, in the sales table, for the following combination of keys :-
pr_id = '23453'
tm_id = 402
the inv_value is null -- Query 1
In the view, if I execute the query,
select * from vw_sales where pr_id = '23453' and tm_id = 402, then I get null as the inv_value, which is correct.
But, if I just do a :-
select * from vw_sales -
then for pr_id = '23453' and tm_id = 402, I have the value as 24.344!!!!
I have no idea how I am getting this.
I removed the view and just executed the select statement, even then I am getting the value as 24.344!!!
I included the rowid also into the query.
Both the queries (1 & 2) return the same row id
Please help

Answer 1

But, that is not the problem I am facing.
If I write the query,
select * from vw_sales
I get (among a lot of rows):-
pr_id    tm_id    cust_id    inv_value
23453 402 452 24.3444
But, if I execute the following query -
select * from vw_sales where pr_id = 23453
then I get (among a lot of rows)
pr_id    tm_id    cust_id    inv_value
23453 402 452 (null)