tbl_task                 tbl_attachments                         
id    name               id    task_id    file
1     Fix Bug            1     1          screenshot.jpg
2     Test               2     1          trace_output.txt
3     Upload

tbl_task_attachment
id   name          file
1    Fix Bug       screenshot.jpg
2    Test          NULL
3    Upload        NULL

select t.id
     , t.name
     , a.file
  from tbl_task as t
left outer
  join tbl_attachments as a
    on a.task_id = t.id
   and a.id
     = ( select max(id)
           from tbl_attachments
          where task_id = t.id )

SELECTtbl_subtask.id, tbl_subtask.name, tbl_attachment.attachment
FROM tbl_task
LEFT JOIN tbl_attachment ON tbl_attachment.subtask_id = tbl_subtask.id
AND tbl_attachment.id = (
SELECT max( id )
FROM tbl_attachment
WHERE tbl_attachment.subtask_id = tbl_subtask.id )

#1064 - You have an error in your SQL syntax.  Check the manual that corresponds to your MySQL server version for the right syntax to use near 'select max(id)
           from tbl_attachment
          where