Since no one else has said anything about it, you don't have 'slam' all of your SQL code together, you can format it nicely:

$dbh->prepare('
    SELECT message_table.message_id, message_table.message_date, 
    message_table.message_time,message_table.message_sender_name,
    message_table.message_to_name, message_table.department_id
    FROM department_table 
    INNER JOIN message_table 
    ON department_table.department_id = message_table.department_id
    WHERE message_table.department_id = ?
');
[download]

much easier to find errors that way - but as said previously, the SQL is not the problem, it was your method of getting the data. I hope you find this helpful in the future, none the less.

Jeff

R-R-R--R-R-R--R-R-R--R-R-R--R-R-R--
L-L--L-L--L-L--L-L--L-L--L-L--L-L--