My personal preference is for the ANSI standard syntax, I really find that seperating out the joins from the other conditions helps me understand more easily what a query is trying to achieve. It also helps debugging IMO.
As for bugs, well there was a famous bug in 9.0.1 (base release) that rendered the database insecure, but I can't say that since then I have come across any great instances of wrong results with them - and I'd wager they were fewer than wrong results due to my not writing a query accurately first time. You could certainly look at the known issues lists (I referred to them at http://orawin.info/services/index.php?option=com_content&task=view&id=65&Itemid=34) and the fixed bugs lists in 10.2.0.2 and 18.104.22.168.
So I'd say that by and large my experience has been positive and that I find the style a lot easier to understand.
I also found that when reading about ANSI joins at asktom.oracle.com, but I notice that Oracle seems to be recommending the ANSI outer join syntax since it allows you to write queries that couldn't be written with the (+) operator. However, all the queries I have written so fat that use outer joins can be written with the (+) operator.
The main thing I gather from the description below is that, perhaps, Oracle intends to add enhancements to the ANSI join syntax that it won't add to the old-style join syntax? (e.g. the last 3 items in your documentation excerpt: A WHERE condition containing the (+) operator cannot be combined with another condition using the OR logical operator; A WHERE condition cannot use the IN comparison condition to compare a column marked with the (+) operator with an expression; A WHERE condition cannot compare any column marked with the (+) operator with a subquery.)
My question, I guess, is have many people run into bugs with ANSI joins, or are the bugs rare and only happening with very convoluted queries?
------------------------------ *De :* Allen, Brandon [mailto:Brandon.Allen@xxxxxxxxxxx] Here is what Oracle has to say about it - from http://download-west.oracle.com/docs/cd/B19306_01/server.102/b14200/queries006.htm :
Oracle recommends that you use the FROM clause OUTER JOIN syntax rather than the Oracle join operator. Outer join queries that use the Oracle join operator (+) are subject to the following rules and restrictions, which do not apply to the FROM clause OUTER JOIN syntax:
You cannot specify the (+) operator in a query block that also contains FROM clause join syntax. -
The (+) operator can appear only in the WHERE clause or, in the context of left-correlation (that is, when specifying the TABLEclause) in the FROM clause, and can be applied only to a column of a table or view. -
If A and B are joined by multiple join conditions, then you must use the (+) operator in all of these conditions. If you do not, then Oracle Database will return only the rows resulting from a simple join, but without a warning or error to advise you that you do not have the results of an outer join. -
The (+) operator does not produce an outer join if you specify one table in the outer query and the other table in an inner query. -
You cannot use the (+) operator to outer-join a table to itself, although self joins are valid. For example, the following statement is not valid:
-- The following statement is not valid: SELECT employee_id, manager_id FROM employees WHERE employees.manager_id(+) = employees.employee_id;
However, the following self join is valid:
SELECT e1.employee_id, e1.manager_id, e2.employee_id FROM employees e1, employees e2 WHERE e1.manager_id(+) = e2.employee_id;
The (+) operator can be applied only to a column, not to an arbitrary expression. However, an arbitrary expression can contain one or more columns marked with the (+) operator. -
A WHERE condition containing the (+) operator cannot be combined with another condition using the OR logical operator. -
A WHERE condition cannot use the IN comparison condition to compare a column marked with the (+) operator with an expression. -
A WHERE condition cannot compare any column marked with the (+) operator with a subquery.
------------------------------ *From:* oracle-l-bounce@xxxxxxxxxxxxx [mailto: oracle-l-bounce@xxxxxxxxxxxxx] *On Behalf Of *Jacques Kilchoer
Let us suppose that I were to be writing a PL/SQL package that will be installed on a variety of databases in my company, and not all the databases are at the same version or patch level (but all are 9.2 and up). Would it be a good idea to use ANSI join syntax in the queries in the package? Knowing that a non-negligeable portion of the queries will be using outer joins? When I search on Metalink, I see bugs relating to the ANSI join syntax, but I also see bugs reported against the (+) style outer join syntax. Of the bugs I see mentioned on Metalink, many were "unpublished" bugs so I couldn't see the details.
I was thinking of using the ANSI join syntax because it is supposed to be easier to read and understand for people coming from non-Oracle environments, more portable, perhaps even "the wave of the future" (?) as I heard it described in one presentation.
Would it be a mistake to use the ANSI join syntax? Should I stick with the old-fashioned Oracle syntax for another year or so?
-- Niall Litchfield Oracle DBA http://www.orawin.info