Hi I want to set the session id to a value after evaluating the request_time using a case when statement.

here 's the table
Code:
userinput_id         session_id          request_time               keyword
     1                                   2011-03-04 08:23:45        free    
     2                                   2011-03-04 08:25:50        free
when the keyword is entered request_time...