I'm quite new to Access programming. I was trying to make a table named Transactions. This table contains two look-up columns from the table Banks called "Bank Name" and "Account Number". For each bank there is only one corresponding account number. I want this account number automatically to appear in the column when a bank name is chosen in another column.

Does someone have a good advise for me?

Look at the example on this thread (http://www.access-programmers.co.uk/forums/showthread.php?t=69201)

If you're trying to do this in a table then you can't; it happens on a form.

So, if you've duplicated two lookup fields in a second table your structure is incorrect.

It should be:

tblBanks
BankID
BankName
AccountNumber

tblTransactions
TransactionID
BankID

The BankID is related and joined in query.

Thanks a lot! I will try this out now.

I tried it out now, but it still doesn't go. Probably I made some mistakes when designing the form and it is still not linked together.
I created a query and a form with the fields BankID, BankName, AccountNumber, InvoiceIDTransactionID and some others and linked
- TblBanks and TblTransactions with the field BankID,
- TblTransactions and TblInvoices with InvoiceID.
Then I created a form with the same fields. But still it is the same sh..
Shall I insert any criteria in the query or in the form and if yes how?
Thanks in advance!

Quick demo:

And do a search on normalisation - hopefully that will help with the conceptual understanding.