Hi Heidi,
The Left Outer Join will return all rows from the left hand table that match your selection criteria even if there is not a correpsonding record in the joined to table. That is to say that if you have a record in QMEL but there isn't a correpsonding record in MAKT, then a left outer join will still return those rows for QMEL.
I hope you are selecting the table join option, In layout mode enter the table names in Joined tables tab. Select the 2 tables using check boxes and select the join type as left outer join and click on define condition. select the '=' sign and leave the value blank.
Regards,