The following restrictions apply to outer joins when used to define a join index.
- FULL OUTER JOIN is not valid.
- When you specify a LEFT or RIGHT outer join, the following rules apply:
- The outer table joining column for each condition must be contained in either column_1_name or column_2_name.
- The inner table of each join condition must have at least one non-nullable column in either column_1_name or column_2_name.