Yes, you can join on any column, FK need not be defined.
Get departments (include those that do not have employees or
managers) and their employees and their managers:
select d.*, e.*, m.* from (department d left outer join employee e on
e.dept_id=d.id) left outer join employee m on e.mgr_id=m.id
will work if PK and FK are not defined. But you may want to have
indexes on your join columns for performance.
Regards,
Ali
At 05:55 AM 9/29/2006, you wrote:
Hi all,
i am pretty new to Derby so maybe this is a stupid question, but i
couldn't find it in the documentation:
is there a way in Derby to combine OUTER JOINS on one table?
For example:
we have a MAIN table and some SUB tables (SUB1, SUB2...) which all
contain MAIN's primary key.
Is it possible to create a select that can see the MAIN table
weither or not the SUB tables have records linked to MAIN?
Thanx
