Must have two instances of the table to create a self-join.

You have two different tables in the Table pane and have defined a self-join by using the same table name in the Left and Right boxes in the Joins dialog box.

• To create a self-join, you must have two instances of the same table in the Table pane.
• To join two different tables, you must use one of the tables for the left side of the join and the other table for the right side of the join.