I have a database with account numbers and card numbers. I match these to a file to update any card numbers to the account number, so that I am only working with account numbers.

I created a view linking the table to the account/card database to return the Table ID and the related account number, and now I need to update those records where the ID matches with the Account Number.

This is the Sales_Import table, where the account number field needs to be updated:

LeadID  AccountNumber
147         5807811235
150         5807811326
185         7006100100007267039

And this is the RetrieveAccountNumber table, where I need to update from:

LeadID  AccountNumber
147         7006100100007266957
150         7006100100007267039

I tried the below, but no luck so far:

UPDATE [Sales_Lead].[dbo].[Sales_Import] 
SET    [AccountNumber] = (SELECT RetrieveAccountNumber.AccountNumber 
                          FROM   RetrieveAccountNumber 
                          WHERE  [Sales_Lead].[dbo].[Sales_Import]. LeadID = 
                                                RetrieveAccountNumber.LeadID) 

It updates the card numbers to account numbers, but the account numbers gets replaced by NULL