How to do MySQL User Accounting
Your only recourse would be to activate the slow log and use it as a MyISAM table. By default, the slow log would normally be a text file. However, a general_log table was provided in newer release of MySQL as a CSV table.

mysql&gt; use mysql
Database changed
mysql&gt; show create table slow_log\G
*************************** 1. row ***************************
       Table: slow_log
Create Table: CREATE TABLE `slow_log` (
  `start_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  `user_host` mediumtext NOT NULL,
  `query_time` time NOT NULL,
  `lock_time` time NOT NULL,
  `rows_sent` int(11) NOT NULL,
  `rows_examined` int(11) NOT NULL,
  `db` varchar(512) NOT NULL,
  `last_insert_id` int(11) NOT NULL,
  `insert_id` int(11) NOT NULL,
  `server_id` int(10) unsigned NOT NULL,
  `sql_text` mediumtext NOT NULL,
  KEY `start_time` (`start_time`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COMMENT='Slow log'
1 row in set (0.03 sec)

mysql&gt;


Make sure you have this in my.cnf and then restart mysql if you had to add this:

[mysqld]
log-output=TABLE
log-slow-queries
long-query-time=0.00001


Next, convert the table to MyISAM and index it on the needed columns:

SET @old_log_state = @@global.slow_query_log;
SET GLOBAL slow_query_log = 'OFF';
ALTER TABLE mysql.slow_log ENGINE = MyISAM;
ALTER TABLE mysql.slow_log ADD INDEX starttime_index (start_time);
ALTER TABLE mysql.slow_log ADD INDEX db_starttime_index (db,start_time);
SET GLOBAL slow_query_log = @old_log_state;
SHOW CREATE TABLE mysql.slow_log\G


You can query the table and retrieve the user and host from mysql.slow_log column user_host.

You can crontab some tasks to copy the data from mysql.slow_log where you need it, may a separate database.

CREATE DATABASE IF NOT EXISTS mystatus;


Perhaps, you can run queries like this:

SET @old_log_state = @@global.slow_query_log;
SET GLOBAL slow_query_log = 'OFF';
ALTER TABLE mysql.slow_log RENAME mystats.slow_log;
CREATE TABLE mysql.slow_log LIKE mystats.slow_log;
SET GLOBAL slow_query_log = @old_log_state;


This will move the slow log elsewhere and start with an empty one.

This may not be a full answer, but I hope this is useful to you as to some direction to take.