ANSI to traditional (+) join syntax

Question

Hi All,
Can anyone pl help me to understand how the diff tables in this tables are joined ( even 1 join would help) as I am not able to differentiate where the first join ended and whether the result is attched to the previous one or what all :(
I am little confused about how to convert this query in ANSI to the traditional (+) sysntax as I am not able to understannd which table is joined to which table and where exactly the previous join ends.
select distinct a.instrument_id       "INSTRUMENT ID",
                a.name                "DESCRIPTION",
                a.DEBT_PRIORITY_CLASS "DEBT PRIORITY CLASS",
                c.alias               "ISIN",
                b.alias               "MDSCURVE"
  from (select distinct i.instrument_id,
                        i.name,
                        case
                          when (mn2.display_name != 'DEBT PRIORITY CLASS' and
                               mn2.display_name is not null) then
                           mn2.display_name
                          else
                           mn1.display_name
                        end "DEBT_PRIORITY_CLASS"
          from instrument i, inst_debt id
          left join marsnode mn1 on (id.debt_priority_class_id = mn1.node_id and
                                    mn1.close_date is null and
                                    mn1.type_id = 58412926883279)
          left join marsnodelink mnl1 on (mn1.node_id = mnl1.node_id and
                                         mnl1.close_date is null and
                                         mnl1.begin_cob_date <=
                                         TO_DATE('27-Oct-2010',
                                                  'DD-Mon-YYYY') and
                                         mnl1.end_cob_date >
                                         TO_DATE('27-Oct-2010',
                                                  'DD-Mon-YYYY'))
          left join marsnode mn2 on (mnl1.parent_id = mn2.node_id and
                                    mn2.close_date is null and
                                    mn2.type_id = 58412926883279)
         where i.instrument_id = id.instrument_id
           and i.end_cob_date > TO_DATE('27-Oct-2010', 'DD-Mon-YYYY')
           and i.close_action_id is null
           and i.product_sub_type_id = 3
           and i.begin_cob_date <= TO_DATE('27-Oct-2010', 'DD-Mon-YYYY')
           and i.instrument_vn = id.instrument_vn) a
  left outer join (select i.instrument_id, ia.alias as alias
                     from instrument i, inst_alias ia, domain d
                    where i.instrument_id = ia.instrument_id
                      and ia.domain_id = d.domain_id
                      and d.name = 'MDSCURVE'
                      and i.close_action_id is null
                      and i.product_sub_type_id = 3
                      and i.begin_cob_date <=
                          TO_DATE('27-Oct-2010', 'DD-Mon-YYYY')
                      and i.end_cob_date >
                          TO_DATE('27-Oct-2010', 'DD-Mon-YYYY')) b on (a.instrument_id =
                                                                      b.instrument_id)
  left outer join (select i.instrument_id, ia.alias as alias
                     from instrument i, inst_alias ia, domain d
                    where i.instrument_id = ia.instrument_id
                      and ia.domain_id = d.domain_id
                      and d.name = 'ISIN'
                      and i.close_action_id is null
                      and i.product_sub_type_id = 3
                      and i.begin_cob_date <=
                          TO_DATE('27-Oct-2010', 'DD-Mon-YYYY')
                      and i.end_cob_date >
                          TO_DATE('27-Oct-2010', 'DD-Mon-YYYY')) c on (a.instrument_id =  c.instrument_id)Specialy the problem with the first left outer join (from instrument i, inst_debt id) , there are many outer joins and i am not able to understand this thing.
Please help me to understand this thing.
Rgds,
Aashish

Answer 1

maybe the comments in this will help...
SELECT   DISTINCT a.instrument_id "INSTRUMENT ID",
                  a.name "DESCRIPTION",
                  a.DEBT_PRIORITY_CLASS "DEBT PRIORITY CLASS",
                  c.alias "ISIN",
                  b.alias "MDSCURVE"
  FROM         (SELECT   DISTINCT
                         i.instrument_id,
                         i.name,
                         CASE
                            WHEN (mn2.display_name != 'DEBT PRIORITY CLASS'
                                  AND mn2.display_name IS NOT NULL)
                            THEN
                               mn2.display_name
                            ELSE
                               mn1.display_name
                         END
                            "DEBT_PRIORITY_CLASS"
                  FROM   instrument i,
                                  inst_debt id
                               LEFT JOIN
                                  marsnode mn1 -- LEFT JOIN from inst_debt to marsnode
                               ON (id.debt_priority_class_id = mn1.node_id
                                   AND mn1.close_date IS NULL
                                   AND mn1.type_id = 58412926883279)
                            LEFT JOIN  -- LEFT JOIN from marsnode to marsnodelink
                               marsnodelink mnl1
                            ON (mn1.node_id = mnl1.node_id
                                AND mnl1.close_date IS NULL
                                AND mnl1.begin_cob_date <=
                                      TO_DATE ('27-Oct-2010', 'DD-Mon-YYYY')
                                AND mnl1.end_cob_date >
                                      TO_DATE ('27-Oct-2010', 'DD-Mon-YYYY'))
                         LEFT JOIN
                            marsnode mn2 -- LEFT JOIN from marsnodelink to marsnode
                         ON (    mnl1.parent_id = mn2.node_id
                             AND mn2.close_date IS NULL
                             AND mn2.type_id = 58412926883279)
                 WHERE   i.instrument_id = id.instrument_id
                         AND i.end_cob_date >
                               TO_DATE ('27-Oct-2010', 'DD-Mon-YYYY')
                         AND i.close_action_id IS NULL
                         AND i.product_sub_type_id = 3
                         AND i.begin_cob_date <=
                               TO_DATE ('27-Oct-2010', 'DD-Mon-YYYY')
                         AND i.instrument_vn = id.instrument_vn) a -- End of in-line view 'a'
            LEFT OUTER JOIN -- LEFT OUTER JOIN from in-line view 'a' to inline view 'b'
               (SELECT   i.instrument_id, ia.alias AS alias
                  FROM   instrument i, inst_alias ia, domain d
                 WHERE       i.instrument_id = ia.instrument_id
                         AND ia.domain_id = d.domain_id
                         AND d.name = 'MDSCURVE'
                         AND i.close_action_id IS NULL
                         AND i.product_sub_type_id = 3
                         AND i.begin_cob_date <=
                               TO_DATE ('27-Oct-2010', 'DD-Mon-YYYY')
                         AND i.end_cob_date >
                               TO_DATE ('27-Oct-2010', 'DD-Mon-YYYY')) b -- End of inline view 'b'
            ON (a.instrument_id = b.instrument_id)
         LEFT OUTER JOIN --LEFT OUTER JOIN from inline view 'a' to inline view 'c'
            (SELECT   i.instrument_id, ia.alias AS alias
               FROM   instrument i, inst_alias ia, domain d
              WHERE       i.instrument_id = ia.instrument_id
                      AND ia.domain_id = d.domain_id
                      AND d.name = 'ISIN'
                      AND i.close_action_id IS NULL
                      AND i.product_sub_type_id = 3
                      AND i.begin_cob_date <=
                            TO_DATE ('27-Oct-2010', 'DD-Mon-YYYY')
                      AND i.end_cob_date >
                            TO_DATE ('27-Oct-2010', 'DD-Mon-YYYY')) c --End of inline view 'c'
         ON (a.instrument_id = c.instrument_id)?
Cheers
Ben