1
不同行
我的表如下所示:如何選擇每組
author_id | doc_id | lang
-----------+--------+----------------
53 | 12642 | English
53 | 12643 | English
53 | 75 | French
55 | 12605 | German
55 | 12606 | German
55 | 12596 | English
,我需要編寫一個查詢做表如下:
author_id | doc_id | lang
-----------+--------+----------------
53 | 12642 | English
53 | 75 | French
55 | 12605 | German
55 | 12596 | English
非常感謝你 –