group by grouping sets用法示例

SELECT CASE
             WHEN aab301 IS not NULL and akb020 is null THEN
              '小计'
             WHEN aab301 IS NULL THEN
              '合计'
             ELSE
              '' ||aab301
          END aab301,akb020,aab001,sum(akc264) from kc24_zy
group by grouping sets ((aab301),(aab301,akb020,aab001),'');