sqlserver写法
创建表
create table test
(id int,
name varchar(1))
insert into test values (1,'a')
insert into test values (2,'a')
insert into test values (1,'a')
insert into test values (1,'a')
insert into test values (2,'a')
执行
select a.id,a.count1,(a.count1+0.0)/b.count2
from
(select id,count(*) count1 from test group by id) a,
(select count(*) count2 from test) b
追问貌似理解错了。你用我的数据源写一下呢