RE: should one use ANSI join syntax when writing an Oracle application?

From: Allen, Brandon <Brandon.Allen_at_OneNeck.com>
Date: Mon, 16 Oct 2006 13:55:35 -0700
Message-ID: <04DDF147ED3A0D42B48A48A18D574C45059E217D@NT15.oneneck.corp>

Here is what Oracle has to say about it - from http://download-west.oracle.com/docs/cd/B19306_01/server.102/b14200/quer ies006.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 TABLE clause) 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_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Jacques Kilchoer

	Sent: Monday, October 16, 2006 1:29 PM
	To: oracle-l
	Subject: should one use ANSI join syntax when writing an Oracle

application?

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?

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Received on Mon Oct 16 2006 - 15:55:35 CDT