表lin(a, b, c)
select *, px = identity(int, 1, 1) into #tb
from lin
go
select *
from #tb as t1
where not exists(
select 1
from #tb as t2
where t1.a = t2.a and t2.px < t1.px)
go
drop table #tb
表lin(a, b, c)
select *, px = identity(int, 1, 1) into #tb
from lin
go
select *
from #tb as t1
where not exists(
select 1
from #tb as t2
where t1.a = t2.a and t2.px < t1.px)
go
drop table #tb