Private messaging system. Listing last message of each conversation

Question

Lets say this is the database structure:

SELECT * FROM `pms` where         


        

Answer 1

select pms.* from pms 
inner join 
    (select max(fecha) as max_fecha,
           if(id_to

Also if id_to and id_from in your table are small enough to prevent overflow in statement (id_to+id_from) here is the simple query:

select pms.* from pms 
inner join 
    (select max(fecha) as max_fecha, id_to+id_from as sum_id
      from pms where id_to = 1 or id_from = 1 
         group by id_to+id_from) t 
     on ((pms.id_to+pms.id_from)=t.sum_id) 
        and (pms.fecha=t.max_fecha)
 where pms.id_to = 1 or pms.id_from = 1