Help on outer joins

Question

here is the query with Four tables as outer joins
select A.student, B.race, B.sex, B.bdate, trunc(C.cdate-B.bdate)/365.25) "age",
A.randomno, A.randomdt, min(D.vdate), max(D.vdate) E.tdate, E.termrsn
from case A, hist B, ent C, log D, ter E
where A.randomno > 0
and A.del IS NULL
and B.del IS NULL
and B.ndone IS NULL
and B.seq = 0.02
and C.del IS NULL
and c.ndone IS NULL
and D.del IS NULL
and D.ndone IS NULL
and E.del IS NULL
and E.ndoe IS NULL
and average > 0
and (B.student = A.student (+))
and (C.student = A.student (+))
and (E.student = A.student (+))
and (D.student = A.student (+))
group by A.student, B.race, B.sex, B.bdate, trunc(c.cdate-b.bdate)/365.25), A.randomno,
A.randomdt , E.vdate, E.termrsn
=============================================
next query with outer joins but with subqueries in the from clause
select A.student, B.race, B.sex, B.bdate, trunc(C.cdate-B.bdate)/365.25) "age",
A.randomno, A.randomdt, min(D.vdate), max(D.vdate) E.tdate, E.termrsn
from A,
(select race, sex, bdate, student from hist
where del IS NULL and ndone IS NULL and seq = 0.02) B,
(Selcet cdate, student from ent
where del IS NULL and ndone IS NULL ) C,
(Select vdate, student from log
where del IS NULL and ndone IS NULL and average > 0) D,
(Select vdate, termrsn, student from ter
where del IS NULL and ndone IS NULL ) E
(where A.randno >0) and A.del IS NULL
and (A.student = B.Student (+))
and (A.student = C.Student (+))
and (A.student = E.Student (+))
and (A.student = D.Student (+))
group by A.student, B.race, B.sex, B.bdate, trunc(c.cdate-b.bdate)/365.25), A.randomno,
A.randomdt , E.vdate, E.termrsn
This two queries runs fine....but the second query gives correct records(WHICH IS WHAT I AM EXPECTING)
The previous query gives 4 records less.
Does Oracle support outer joins with out subquerys in the from clause or i am doing some thing wrong here(I mean syntax error)
DO I need to write subqueries for every outer join to get the correct record.
If I do outer joins with one or two tables with out subqueries.....I do not have any problem
Thanks
Rama
null

Answer 1

There are two issues. First Oracle supports outer joins against one table. This means you can do this:
where a.col1 = b.col1(+)
and a.col2 = c.col2(+)
and a.col3 = d.col3(+)
but you can't do this:
where a.col1 = b.col1(+)
and b.col2 = c.col2(+)
because this outer joins to more than one table.
The second issue is that you must outer join to all columns of a table. So you can't do this:
where a.col1 = b.col1(+)
and b.col2 is null
but you can do this:
where a.col1 = b.col1(+)
and 'X' = nvl( b.col2(+), 'X' )
null