Alex,

Try

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

>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