首先创建测试表、添加数据。
create table #t(a int,b int,c int,d int,e int)
insert into #t values(1,2,3,4,5)
insert into #t values(1,2,3,4,6)
insert into #t values(1,2,3,4,7)
insert into #t values(1,2,3,4,8)
insert into #t values(1,3,3,4,5)
insert into #t values(1,3,3,4,6)
insert into #t values(1,3,3,4,8)
insert into #t values(1,3,3,4,7)
insert into #t values(2,2,2,4,5)
insert into #t values(2,2,3,4,6)
insert into #t values(2,2,4,4,7)
insert into #t values(2,2,5,4,8)
insert into #t values(2,3,6,4,5)
insert into #t values(2,3,3,4,6)
insert into #t values(2,3,3,4,8)
insert into #t values(2,3,3,4,7)
情况一：只有一个分类汇总列时，只需要一个合计。只需要增加with rollup即可。
select case when grouping(a)=1 then '合计' else cast(a as varchar) end a,
sum(b),sum(c),sum(d),sum(e) from #t group by a with rollup
情况二:有多个分类汇总列，只需要一个合计.增加rollup之后，需要增加判断。
select case when grouping(a)=1 then '合计' else cast(a as varchar) end a,
b,
sum(c),sum(d),sum(e) from #t
group by a,b with rollup
having grouping(b)=0 or grouping(a)=1
select case when grouping(a)=1 then '合计' else cast(a as varchar) end a,
b,
c,
sum(d),sum(e) from #t
group by a,b,c with rollup
having grouping(c)=0 or grouping(a)=1
情况三：有多个分类汇总列，需要全部的小计和合计。
select case when grouping
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1 重复使用编程代码，减少编程开发时间。
2 隐藏SQL细节，把SQL繁琐的工作留给数据库开发人员，而程序开发员则集中处理高级编程 ......
select f.tablespace_name,a.total,u.used,f.free,round((u.used/a.total)*100) "% used", round((f.free/a.total)*100) "% Free"
from
(select tablespace_name, sum(bytes/(1024*1024)) total
from dba_data_files group by tablespace_name) a,
(select tabl ......
