SQL To Get The Latest Instance Of User Action

Hi

Im in a bit of a pickle due to a large amount of data in a table and the query Im running is taking a very long time, so Id like to get some advice from the guys here to see if it can be done another way.

Ok, so heres the background. I have a table, see desc below, that contains transaction data for a number of users. Each user may have more than one transaction. In each row the SEQUENCENUMBER column is populated with a timestamp for the transaction, so I was using this to get the latest. However there are over 1 million rows in the table and the query below has taken over 12 hours so far to run. Has anyone any ideas on how I can make life a little easier for myself here?

SQL Query

Code:


select user,recipient,sequencenumber from trans_database where user IN (select distinct(user) from trans_database)
order by sequencenumber desc limit 1;



Table Layout

Code:


ID int(10) unsigned (NULL) NO PRI (NULL) auto_increment select,insert,update,references
RECIPIENT varchar(5) latin1_swedish_ci NO select,insert,update,references
DONOR varchar(5) latin1_swedish_ci NO select,insert,update,references
USER varchar(20) latin1_swedish_ci NO select,insert,update,references
UPDATETYPE varchar(10) latin1_swedish_ci NO select,insert,update,references
REPFLAG varchar(1) latin1_swedish_ci NO select,insert,update,references
OPFIELD varchar(20) latin1_swedish_ci NO select,insert,update,references
SEQUENCENUMBER varchar(18) latin1_swedish_ci NO select,insert,update,references
REQUESTDTS varchar(20) latin1_swedish_ci NO select,insert,update,references
PROCESSED varchar(1) latin1_swedish_ci YES (NULL) select,insert,update,references