显示分类对应的文章数目,为空的设置为0,按文章数目排序
select a.id ,COUNT(b.id) as num from phphi_category a left join phphi_article b on b.cid=a.id GROUP BY a.id order by num desc;
程序员是一种算法,好的程序员是一个最优的算法
select a.id ,COUNT(b.id) as num from phphi_category a left join phphi_article b on b.cid=a.id GROUP BY a.id order by num desc;