mysql5.7分组查询group by，分组查询并且显示每组时间最新的一条记录

SELECT
**
FROM
t_group_album a
LEFT JOIN (
SELECT
f_aid,
COUNT(f_aid) pictureNum,
group_concat(
f_image_url
ORDER BY
f_update_time DESC
) f_image_url
FROM
t_group_picture
GROUP BY
f_aid
) p ON a.f_id = p.f_aid
WHERE
f_gid = #{gid,jdbcType=CHAR}
ORDER BY
f_create_time DESC;