I try to update one field of the Table1 from Table2:

Update ;
     Table1 ;
from ;
     Table2 ;
set ;
     FieldToBeUpdated = NVL(Table2.FieldToUpdateWith,"") ;
where ;
     Table2.KeyField = Table1.KeyField

That is easy, but I would like to enchance this SQL-Statement so that in all Records of Table1 that do not match the Where-Clause, the Table1.FieldToBeUpdated will be set to "", as in the statement:

Update ;
    Table1 ;
set ;
    FieldToBeUpdated="" ;
where ;
    Table1.KeyField not in ;
       (select KeyField from Table2)

But I'd like it all to be in one statement...

Thanks for help