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Top Forums Shell Programming and Scripting Select record with MAX value in MySQL Post 302433402 by pludi on Tuesday 29th of June 2010 01:03:20 PM
Old 06-29-2010
It's been a while since I've spoken MySQL... but I'd do it this way
Code:
CREATE UNIQUE INDEX IX_uploaded_name_time ON uploaded ( file_name, file_time )

But the ALTER TABLE syntax (the first one) should get you the same result. If not, you can always drop and re-create the index.

It would be interesting tho to see the comparison of the execution timing and EXPLAIN plan with and without the indices.

And if you want to optimize further, here's an article on how to use the MySQL profiler.
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mysql(1)							  MySQL database							  mysql(1)

NAME
mysql_fix_privilege_tables - Fixes MySQL privilege tables. SYNOPSIS
mysql_fix_privilege_tables [mysql_root_password] DESCRIPTION
This scripts updates the mysql.user, mysql.db, mysql.host and the mysql.func tables to MySQL 3.22.14 and above. This is needed if you want to use the new GRANT functions, CREATE AGGREGATE FUNCTION or want to use the more secure passwords in 3.23 If you get 'Access denied' errors, run the script again and give the MySQL root user password as an argument. SEE ALSO
isamchk(1), isamlog(1), mysql(1), mysqlaccess(1), mysqladmin(1), mysqld(1), mysqld_multi(1), mysqld_safe(1), mysqldump(1), mysqlshow(1), mysql_zap(1), perror(1), replace(1) For more information please refer to the MySQL reference manual, which may already be installed locally and which is also available online at http://www.mysql.com/doc/en/ BUGS
Please refer to http://bugs.mysql.com/ to report bugs. AUTHOR
This manpage was written by Christian Hammers <ch@debian.org>. MySQL is available at http://www.mysql.com/. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +--------------------+------------------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +--------------------+------------------------------------+ |Availability | SUNWmysqlr, SUNWmysqlu, SUNWmysqlt | +--------------------+------------------------------------+ |Interface Stability | External | +--------------------+------------------------------------+ NOTES
Source for mysql is available on http://opensolaris.org. MySQL 4.0 17 March 2003 mysql(1)
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