Exclude Debit Transactions - oracle

Question

I have a need to select records from transactions table excluding certain transactions.
Bellow is a sample output of my tables.
TB_ACCOUNTS
CUSTCD ACCTNO PRDCD
100 10001 SATF
100 10002 SATF
200 10003 CUS
TB_TRANSACTIONS
TXNNO TXDATE ACCTNO CUSTOMER_NO TXAMT CASHFLOWTYPE
TX1 18-Jul-16 10001 100 5000 CR
TX2 18-Jul-16 10002 100 5000 DR
TX3 18-Jul-16 10003 200 3000 DR
TX4 18-Jul-16 10001 100 3000 CR
I want to select credit transactions where PRDCD is 'SATF' and exclude transfers between own accounts. For example customer 100 PRDCD is SATF and has two accounts. I want my select query to exclude credit transaction of amount 5000 because the debit account also belongs to the same customer. But include credit transaction of 3000 amount because the debit account is of different customer and type is not SATF.
So far I got bellow query but the output I'm getting is completely wrong.
select * from TB_TRANSACTIONS AB inner join TB_ACCOUNTS AC
on AB.ACCTNO=AC.ACCTNO
where AB.CASHFLOWTYPE='CR'
and AC.PRDCD='SATF'
and AB.TXNNO=
(select TXNNO from TB_TRANSACTIONS A, TB_ACCOUNTS B
where A.ACCTNO=B.ACCTNO
and A.TXAMT=AB.TXAMT
and A.CASHFLOWTYPE='DR'
and B.PRDCD=AC.PRDCD)
How to achieve the desired result?

Answer 1

You could use something like here:
select txnno, txdate, acctno, customer_no, txamt, cashflowtype, prdcd
from (
select t.*, a.prdcd,
count(distinct customer_no) over (partition by txdate, txamt) cnt
from tb_transactions t join tb_accounts a on t.acctno = a.acctno )
where cnt = 2 and cashflowtype = 'CR' and prdcd = 'SATF'
Here I assumed that txamt is unique for each date. I strongly suspect that this may be wrong assuption so be warned.
But there is nothing except this column that tells us that two rows belongs to the same operation.
In first query I used count() in analytic version. There are also possible other solutions, for instance (not) exists:
select *
from tb_transactions t join tb_accounts a on t.acctno = a.acctno
where
not exists (
select 1 from tb_transactions tt join tb_accounts ta on tt.acctno = ta.acctno
where tt.txdate = t.txdate and tt.txamt = t.txamt
and tt.cashflowtype = 'DR' and tt.customer_no = t.customer_no)
and cashflowtype = 'CR' and prdcd = 'SATF'
(sorry for any language mistakes)