1、分组之后再合计

关键字： grouping sets （（分组字段1，分组字段2），（））

select sylbdm ,count(sylbmc) as rs,round(count(sylbmc)/(select count(sylbmc) from bmk),4)*100 || '%' as bl
from bmk 
GROUP BY grouping sets ((sylbdm ),())

2、显示不为空的值

关键字： coalesce合并多个字段，显示第一个不为null的值

        select COALESCE(sylbdm, '合计')                                          as lx,
               count(sylbdm)                                                     as rs,
               ROUND(COUNT(sylbdm) / (select count(*) from BMK) * 100, 2) || '%' AS bl
        from BMK
        group by GROUPING SETS ((sylbdm), ())