Oracle-L: Query tuning with tablename alias

From: Hopper, Wendy S <wendy.hopper_at_eds.com>
Date: Wed, 20 Nov 2002 10:13:30 -0800
Message-ID: <F001.005081AB.20021120101330@fatcity.com>

Hello list.

I have recently been tasked with trying to optimize some slow performing queries (Oracle 8.1.7) for an application that generates reports in a data warehouse type environment. I have noticed in most of the queries that the table names have been aliased, but not used elsewhere in the query.

IE. SELECT table1.column1,

                      table1.column2,
                      table2.column1
       FROM     table1 A,
                      table2 B
       WHERE   table1.key = table2.key;

Are there any advantage/disadvantages to giving these tables aliases and not using them anywhere else? I am thinking that if the tables have been assigned alias names, they should be referred to by alias names, but I guess I have not seen anything documented on this officially. These queries join tables against remote tables in a different instance, if that makes a difference. Any insight on this would be great.

Thanks.

Wendy Hopper

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Author: Hopper, Wendy S
INET: wendy.hopper_at_eds.com

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