Re: Optimize sub query with large group by

[Rick James]

What determines "the most recent person to access any particular object" ? I see no timestamp. Maybe ID, if it is an AUTO_INCREMENT? But there is no ORDER BY.

It sounds like you need what I call the 'group by trick':
http://forums.mysql.com/read.php?10,280124 (limiting rows returned)
http://forums.mysql.com/read.php?10,266585 (How does group by algorithm works?)
http://forums.mysql.com/read.php?10,236805 (Complex Select with Min/Max Syntax)
http://forums.mysql.com/read.php?10,400775 (Assistance required for query with subquery)
http://forums.mysql.com/read.php?10,396680 (Slow Query)
http://forums.mysql.com/read.php?10,394154 (Require help to formulate a query.)
http://forums.mysql.com/read.php?20,389565 (query returns unwanted duplicates)
http://forums.mysql.com/read.php?10,387554 (aggreate data)
http://forums.mysql.com/read.php?10,373984 (select max date in Inner Join)
http://forums.mysql.com/read.php?20,291994 (create function help)
http://forums.mysql.com/read.php?10,290067 (Help with minimum/group by)
http://forums.mysql.com/read.php?10,284734 (max function)
http://forums.mysql.com/read.php?52,272271 (Subquery and JOIN's)
http://forums.mysql.com/read.php?10,250033 (Listing threads by newest posts?)