select case when select Sum(金额) from table is 0 then null else sum(金额)/(select Sum(金额) from table) from table group by 客户 where 时间 >=s1 and 时间<s2 and
客户 = kh end
select (b1/a1)*100 as Get_Data
from (select sum(金额) as a1 from tabel) a,
(select sum(金额) as b1 from tabel where customer_no=some_no and
table.time>=some_time1 and table.time<=some_time2) b