As everyone has mentioned - you should always assume the data comes back randomly - even if the table is completely static and there have been no inserts or updates, but it's even more subtle than that.
When you port your application to a database than allows your queries to run multi-threaded (Oracle, DB2, SQL Server) - every query process will return a chunk of the data and one process will mastermind and glue the chunks together. There is no guarantee that the chunks will always be glued in the same order - unless ORDER BY has been specified. People who get sloppy in single threaded databases and only use a GROUP BY without an ORDER BY, relying on the fact that the GROUP BY does a sort and makes the ORDER BY unnecessary - get a rude awakening when they move to a multi-threaded database where every query process returns its chunk sorted but the different chunks are glued out of sequence unless you explicitly specified the ORDER BY. So - certain errors will never become apparent in single-threaded MySQL or Microsot Access, but will sting you when upgrading to a multi-threaded database. Therefore - beware - and always specify ORDER BY if you want your data sorted. In a message dated 5/3/2004 1:39:48 PM Eastern Daylight Time, [EMAIL PROTECTED] writes: > > My boss says that if you do a select statement against a table the > result set always comes back in the same order. I say that this is a > myth and that the result is random, except when some ordering is > specified in the SQL statement. > > Who is right? Is this behavior specified by ANSI or ISO? > > Best Regards, > Boyd E. Hemphill > [EMAIL PROTECTED] > Triand, Inc. > www.triand.com > O: (512) 248-2287 > M: (713) 252-4688 > > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: > http://lists.mysql.com/[EMAIL PROTECTED] > > > > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
