ANSI SQL Syntax Vs Old Syntax

Question

Hi,
Is there a performance difference between ansi and old syntax.
The following query
SELECT ITD.display_description
FROM structure_child SC
RIGHT OUTER JOIN structure S ON SC.structure_id = S.structure_id
INNER JOIN structure_level SL ON SL.structure_level_id = S.structure_level_id
INNER JOIN item_type_naming ITN ON ITN.structure_id = S.structure_id
INNER JOIN item_type_description ITD ON ITN.item_type_description_id = ITD.item_type_description_id
AND item_type_id = p_item_type_id
WHERE ( S.structure_id = p_structure_id OR S.structure_id = 0)
and itd.item_type_id = p_item_type_id
ORDER BY structure_level
Runs much slower than the old style query
SELECT ITD.DISPLAY_DESCRIPTION
FROM structure S, structure_child SC, structure_level SL,item_type_naming ITN,
item_type_description ITD
WHERE SC.structure_id(+) = S.structure_id
AND SL.structure_level_id = S.structure_level_id
AND ITN.structure_id = S.structure_id
AND ITN.item_type_description_id = ITD.item_type_description_id
AND item_type_id = p_item_type_id
AND (S.structure_id = p_structure_id OR S.structure_id = 0)
ORDER BY structure_level
Any reasons why this is the case. Also is there any hint I can give to improve the performance.

Answer 1

They ought to be the same.
Be sure to run the query twice to ensure the extra time doesn't including parsing, etc.
Do you get the same results?
Are the explain/execution plans the same?
The only caveat I can think of with ANSI joins is that there is a problem using them over a dblink in which one of the remote tables has a LOB column, an error is generated it that case...
Steve