Ora-1445 in an interactive report

Question

I'm running into an issue adding an outer join to a SQL statement in an interactive report. When I add (+) to the where clause the I get the following error.
1 error has occurred
* The report query needs a unique key to identify each row. The supplied key cannot be used for this query. Please edit the report attributes to define a unique key column. ORA-01445: cannot select ROWID from, or sample, a join view without a key-preserved table
When I run the sql in the SQL workshop and it works fine and returns the results I expect. As soon as I add the (+) to the report, it fails. I have duplicated this issue on the apex.oracle.com site and can provide the details on how to reproduce the error.
Thanks,
Bruce

Answer 1

I tried to convert this where clause to the left outer join but it give me a table does not exist error. Perhaps you can see what I've done wrong. Here's the where clause.
from ni_requests a,
(select chain_num, chain_name, chain_seq_num from apex_so.cs_chain) b,
APEX_SO.ASSOCIATE ASSOCIATE,
(select NEW_ITEM_SEQ_NUM, assignor_comments, ASSIGNEE_ASSOC_SEQ_NUM from NI_ASSIGNEE where DATE_UNASSIGNED is null) ni_assignee
where a.NEW_ITEM_SEQ_NUM = NI_ASSIGNEE.NEW_ITEM_SEQ_NUM(+)
and NI_ASSIGNEE.ASSIGNEE_ASSOC_SEQ_NUM = ASSOCIATE.ASSOC_SEQ_NUM(+)
and a.chain_seq_num = b.chain_seq_num and NI_PROC_PHASE_SEQ_NUM = 14
The issue is on the outer from the ni_assignee to the associate table. This (+) spec causes the error in the interactive report but not in the workshop.
I tried this, maybe I did it incorrectly...
from ni_requests a,
(select chain_num, chain_name, chain_seq_num from apex_so.cs_chain) b,
left outer join APEX_SO.ASSOCIATE on NI_ASSIGNEE.ASSIGNEE_ASSOC_SEQ_NUM = ASSOCIATE.ASSOC_SEQ_NUM,
(select NEW_ITEM_SEQ_NUM, assignor_comments, ASSIGNEE_ASSOC_SEQ_NUM from NI_ASSIGNEE where DATE_UNASSIGNED is null) ni_assignee
where a.NEW_ITEM_SEQ_NUM = NI_ASSIGNEE.NEW_ITEM_SEQ_NUM(+)
and a.chain_seq_num = b.chain_seq_num and NI_PROC_PHASE_SEQ_NUM = 14
The above here give the table not found.
Thanks,
Bruce