SQL 不新增表 把一张表定义成两张

Question

select ＊from wenjianming a
select a.* from
(select * from a) tba
inner join
(select * from a) tbb
on balabala
是想对比同一张表某个时间段内数据的差别 但不新增表
这个代码有啥问题吗！为啥跑不出来啊:(

Answer 1

with a as (select * from 表)
select a1.*,a2.* from 
(select * from a)  a1
join 
(select * from a)  a2
on a1.id=a2.id