Query across two tables

[anonymous]

Please help me with this query..
I have two tables..One is customer details table and another transaction details table.
The customer details table has all the details of internal customers..
like following
Cust_id Accnt_id
1 001
2 002
and so on..
The transaction details table has details like
TxnId Acnt_id Type benAcnt DrAcntId
12 001 dep 001 235
13 001 dep 001 002
14 001 with 456 001
15 001 with 003 845
And so on..
What i want is the list of all account ids that 001 has transacted with irrespective of type..Here 001,002,003 are internal customers while 235,456,845 are external customers whose details are not available in customer details table..So i want the list of such external customers transacted with customer 001. Some thing like following,
Acnt_id ExternalAcnt_id
001 235
001 456
001 845 . Please help in forming query for this..

[azimmer]

Please help me with this query..
I have two tables..One is customer details table and another transaction details table.
The customer details table has all the details of internal customers..
like following
Cust_id Accnt_id
1 001
2 002
and so on..
The transaction details table has details like
TxnId Acnt_id Type benAcnt DrAcntId
12 001 dep 001 235
13 001 dep 001 002
14 001 with 456 001
15 001 with 003 845
And so on..
What i want is the list of all account ids that 001 has transacted with irrespective of type..Here 001,002,003 are internal customers while 235,456,845 are external customers whose details are not available in customer details table..So i want the list of such external customers transacted with customer 001. Some thing like following,
Acnt_id ExternalAcnt_id
001 235
001 456
001 845 . Please help in forming query for this..

select X.*
from (
    select Acnt_id, benAcnt as ExternalAcnt_id
    from TRANSACTIONSTABLE
    where benAcnt>='200'
 
    union 
 
   select Acnt_id, DrAcntId as ExternalAcnt_id
   from TRANSACTIONSTABLE
   where DrAcntId>='200') as X
where Acnt_id = '001'
 

[anonymous]

select X.*
from (
    select Acnt_id, benAcnt as ExternalAcnt_id
    from TRANSACTIONSTABLE
    where benAcnt>='200'
 
    union 
 
   select Acnt_id, DrAcntId as ExternalAcnt_id
   from TRANSACTIONSTABLE
   where DrAcntId>='200') as X
where Acnt_id = '001'
 

Its not always that external account id is greater than 200..It can have any id..only thing is that the external ids are not present in customer details table.

[azimmer]

Its not always that external account id is greater than 200..It can have any id..only thing is that the external ids are not present in customer details table.

OK, here it goes:

select X.*
from (
    select Acnt_id, benAcnt as ExternalAcnt_id
    from TRANSACTIONSTABLE
    where benAcnt not in (select Acnt_id from CUSTOMERS)
 
    union 
 
    select Acnt_id, DrAcntId as ExternalAcnt_id
    from TRANSACTIONSTABLE
    where DrAcntId not in (select Acnt_id from CUSTOMERS)) as X
where Acnt_id = '001'