declare @表A table 
(字段1 varchar(2),字段2 varchar(2),字段3 varchar(2))
insert into @表A
select 'aa','bb','cc'

select 字段1 as 新字段 from @表A
union all
select 字段2 from @表A
union all
select 字段3 from @表A

/*
新字段
----
aa
bb
cc
*/