php - group messages by same users -

i have 2 tables .. 1- users,,2-messages

i wrote query doesn't show last subject , need last subject

select (         case when messages.sender = 68314 messages.receiver else messages.sender end         ) user_id,          max(messages.added) last_added,messages.subject,         max(messages.id) last_id,users.username   messages   inner join users on users.id = if(messages.sender = 68314, messages.receiver, messages.sender)  (messages.sender = 68314 or messages.receiver = 68314) , messages.sender!=0   group  (     case when messages.sender = 68314 messages.receiver else messages.sender end )  order last_added desc 

it shows first subject, not last one.

please give query try. first select max(id) of messages of people talking id 68314 assuming created last...and joins messages, , joined users other person's name.

select last_messages.user_id,        m.added last_added,        m.subject,        last_messages.last_id,        u.username messages m inner join   (select if(sender = 68314,receiver,sender) user_id,          max(id) last_id   messages   if(sender = 68314,sender,receiver) = 68314   group user_id   )last_messages   on last_messages.last_id = m.id inner join users u on last_messages.user_id = u.id order last_added; 

sqlfiddle