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Full Discussion: Select record with MAX value in MySQL
Top Forums Shell Programming and Scripting Select record with MAX value in MySQL Post 302433688 by radoulov on Wednesday 30th of June 2010 08:48:29 AM
Old 06-30-2010
No,
or better still, it depends.

I thought that you were processing the data record by record and at the end you were mass updating the modification time in the files table.

If the modification time update cannot be placed in those one-by-one queries, it's probably better to avoid the approach I suggested.

But as I said it depends.

Initially the problem was the wrong operation (because of the partial group by supported by MySQL), after that the statement was fixed.

Now it's about performance.

If the elapsed of the massive update (single statement -> many rows) is critical, even doing more transactions at a different time (row-by-row, 100 statements for 100 rows) could make sense.

Hope this helps.
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LEARN ABOUT OPENSOLARIS

perror

perror(1)							  MySQL database							 perror(1)

NAME

       perror - describes a system or MySQL error code.

SYNOPSIS

       perror [OPTIONS] [ERRORCODE [ERRORCODE...]]

DESCRIPTION

       Can  be	used  to display a description for a system error code, or an MyISAM/ISAM table handler error code.  The error messages are mostly
       system dependent.

OPTIONS

       -?|--help
	      Displays this help and exits.

       -I|--info
	      Synonym for the above.

       -s|--silent
	      Only print the error message

       -v|--verbose
	      Print error code and message (default).

       -V|--version
	      Displays version information and exits.

EXAMPLE

       shell> perror 64 79 Error code  64:  Machine is not on the network Error code  79:  Can not access a needed shared library

SEE ALSO

       isamchk(1), isamlog(1), mysql(1), mysqlaccess(1), mysqladmin(1), mysqld(1), mysqld_multi(1), mysqld_safe(1), mysqldump(1), mysql_fix_privi-
       lege_tables(1), mysqlshow(1), mysql_zap(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

       Ver 1.0, distribution 4.0.24 Michael (Monty) Widenius (monty@mysql.com), MySQL AB (http://www.mysql.com/).  This  software  comes  with	no
       warranty.   Manual page by L. (Kill-9) Pedersen (kill-9@kill-9.dk), Mercurmedia Data Model Architect / system developer (http://www.mercur-
       media.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							 19 December 2000							 perror(1)
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