How to Use Case statement in Left outer Join using Operator +? - sql

Question

Query:
select /*+ full(c)parallel(c,4) */ a.*
from ioct_inv_item_all a,
(select udac_group_name, function_order , db_region, workflow_type, change_level
from ioct_function_target
where udac_group_name = 'Banner'
and function_name = 'emptyParam'
and workflow_type = 'CHGFCLTR'
and ('emptyParam' = 'emptyParam' or ('CHGFCLTR' != 'NEWITM' AND change_level = 'emptyParam') or ('CHGFCLTR' = 'NEWITM' and change_level = 'Simple') )
and sysdate between effective_from_date and effective_to_date ) b , item_ca c ,product_ca d,assignment_ca ac ,branches b
where a.udac_group_name = 'Banner'
and a.workflow_type = 'CHGFCLTR'
and a.DB_REGION = b.db_region (+)
and a.workflow_type = b.workflow_type (+)
and a.udac_group_name = b.udac_group_name (+)
and a.change_level = b.change_level (+)
and a.product_code = c.product_code(+)
and a.product_issue_num = c.product_issue_num(+)
and a.item_id = c.item_id(+)
and a.customer_id = c.customer_id(+)
and c.product_code = d.product_code(+)
and c.product_issue_num = d.product_issue_num(+)
and c.product_issue_year = d.product_issue_year(+)
and c.customer_id = d.customer_id(+)
and (case when c.contract_assignment_id IS NOT NULL
AND c.contract_assignment_id > 0
THEN c.contract_assignment_id
ELSE d.regular_assign_id
END) = ac.assignment_id(+)
and ('emptyParam' = 'emptyParam' OR ('CHGFCLTR' = 'NEWITM' AND a.eue_normal_ind = 'emptyParam') OR ('CHGFCLTR' != 'NEWITM' AND a.change_level = 'emptyParam') )
and (('emptyParam') IN ('emptyParam') OR a.region IN ('emptyParam'))
and ('emptyParam' = 'emptyParam'
OR (b.function_order is not null and a.assignee_group_seq = b.function_order)
OR (b.function_order is null and 'emptyParam' = 'emptyParam')
Error:
error:
ORA-01417: a table may be outer joined to at most one other table
01417. 00000 - "a table may be outer joined to at most one other table"
*Cause: a.b (+) = b.b and a.c (+) = c.c is not allowed
*Action: Check that this is really what you want, then join b and c first
in a view.
Error at Line: 28 Column: 20
Does any body suggest any alternative to do same thing without using keyword LEFT OUTER JOIN because i do not want to change the structure of sql query already Written?

Answer 1

The basic idea is that you start with a driving table and then outer join it to other tables. If a is your driving table, then
select x
from a,b,c
where a.x = b.x(+)
and a.y = c.y(+)
is the sort of query oracle expects in the join.
If you really want outer join a table with multiple "driving" tables, you can to use a syntax like this, as pointed out in the error description
Assuming you want to outer join "a" to both "b" and "c"
select *
from a,
(select *
from a,c
where c.y = a.y(+)
)
where b.x = a.x(+)
;