Re: Are equi-joins faster than left joins?
I have 3 tables that are 1:1 and will always have a row for a given product,_code & date. If I want to join them together, is it going to be faster to use an equi join or a left join, or does it matter? Who cares, they are -different- things symantically, use the correct type of join for your data and resultset. "Speed" is an implementation issue, a physical property. With regards, Martijn Tonies Upscene Productions http://www.upscene.com Download Database Workbench for Oracle, MS SQL Server, Sybase SQL Anywhere, MySQL, InterBase, NexusDB and Firebird! Database questions? Check the forum: http://www.databasedevelopmentforum.com -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql?unsub=arch...@jab.org
Re: Are equi-joins faster than left joins?
On Thu, Mar 12, 2009 at 8:41 AM, mos wrote: > I have 3 tables that are 1:1 and will always have a row for a given > product,_code & date. If I want to join them together, is it going to be > faster to use an equi join or a left join, or does it matter? > IIRC:With an inner join the optimizer has more latitude to reorganize the join order and can short circuit the process if there is not a corresponding row. This is completely secondary to getting the right result set for your query. If there is the possibility of a row in the parent table not joining and needing to be part of the result then you must use left. -- Rob Wultsch wult...@gmail.com -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql?unsub=arch...@jab.org
Re: Are equi-joins faster than left joins?
IIRC it does not matter. But you can double-check my opinion with EXPLAIN. A. On Thu, Mar 12, 2009 at 11:41 AM, mos wrote: > I have 3 tables that are 1:1 and will always have a row for a given > product,_code & date. If I want to join them together, is it going to be > faster to use an equi join or a left join, or does it matter? > > TIA > Mike >
Are equi-joins faster than left joins?
I have 3 tables that are 1:1 and will always have a row for a given product,_code & date. If I want to join them together, is it going to be faster to use an equi join or a left join, or does it matter? TIA Mike -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql?unsub=arch...@jab.org
