SELECT id, titile, SUM( LENGTH( titile ) ) AS length
FROM  `your_table` 
where author = '".$author."' 
order by length desc

------解决方案--------------------
SQL code

select count(*) as count, author,sum(length(content)), group_concat(title)
group by author
order by count DESC

------解决方案--------------------
一个sql语句搞不定。就用俩foreach。外面是作者，里面是文章标题列表