MySql：最新のレコードを提供しないことを組み合わせて注文およびグループ化

どうすればGROUP BY id_thread id_threadがない場合 テーブルの列？

SELECT * 
FROM contacts 
WHERE id_receiver = 1 
                                 --- GROUP BY id_thread
                                 --- removed 
ORDER BY created DESC
LIMIT 1                          --- only show one row

コメントに基づいて、必要なのは最新のものです（createdの順に並べられています） ）すべてのid_threadの行 、これは別のより複雑なクエリです。この種のクエリには、 [greatest-n-per-group] 。

SELECT c.* 
FROM contacts AS c
  JOIN
    ( SELECT id_thread, MAX(created) AS created 
      FROM contacts 
      WHERE id_receiver = 1  
      GROUP BY id_thread
    ) AS g 
    ON (g.id_thread, g.created) = (c.id_thread, c.created) 
WHERE c.id_receiver = 1