Thanks a lot kimber for sharing this query, it works ok.
Doing a little research i have found the reason for the random results i mentioned above, it seems that the table prefix_message stores the "unread" messages, and the table prefix_message_read stores the "readed" messages.
What i need is to show the total number for read and unread messages.
I have been trying to achieve this, but my SQL knowledge is very limited (although you are helping me a lot).
Could you point me in the right direction with this issue?
Best regards!