求SQL语句，获得表中某字段无重复记录最小值

[robin100]

有表 test_table
id value
1 20
2 20
3 25
4 25
5 30
6 35
7 40
现在要获得value字段的无重复最小的那个记录是： 第5条 30 那个记录。虽然 1、2、3、4条记录比第5条小，但是有重复。请问这个SQL语句应该怎么写呢。

[dawugui]

select min(value) from
(
  select value from tb group by value having count(*) = 1
) t

[dawugui]

create table tb(id  int,   value int)
insert into tb values(1,         20 )
insert into tb values(2,         20 )
insert into tb values(3,         25 )
insert into tb values(4,         25 )
insert into tb values(5,         30 )
insert into tb values(6,         35 )
insert into tb values(7,         40 )

select min(value) from
(
  select value from tb group by value having count(*) = 1
) t

drop table tb

/*
----------- 
30

（所影响的行数为 1 行）
*/

[liangCK]

declare @t table(id int,value int)
insert @t select 1,         20 
insert @t select 2 ,        20 
insert @t select 3  ,       25 
insert @t select 4   ,      25 
insert @t select 5    ,     30 
insert @t select 6     ,    35 
insert @t select 7      ,   40

select top 1 id,value from @t where value in(select value from @t group by value having count(*)=1)
order by value asc

/*
id          value       
----------- ----------- 
5           30

（所影响的行数为 1 行）
*/

[chenhp520]

select top 1 value
from test_table
group by value
having count(*) = 1
order by value

[dawugui]

create table tb(id  int,   value int)
insert into tb values(1,         20 )
insert into tb values(2,         20 )
insert into tb values(3,         25 )
insert into tb values(4,         25 )
insert into tb values(5,         30 )
insert into tb values(6,         35 )
insert into tb values(7,         40 )

select a.* from tb a where value in
(
  select min(value) from
  (
    select value from tb group by value having count(*) = 1
  ) t
)
drop table tb

/*
id          value       
----------- ----------- 
5           30

（所影响的行数为 1 行）
*/

[hqhhh]

create table #tmp(
id int,
value int)

insert into #tmp values(1, 20)
insert into #tmp values(2, 20)
insert into #tmp values(3, 25)
insert into #tmp values(4, 25)
insert into #tmp values(5, 30)
insert into #tmp values(6, 35)
insert into #tmp values(7, 40)
insert into #tmp values(8, 50)


select * from #tmp
where value=(select top 1 value from #tmp group by value having count(*)=1 order by value)

[wzy_love_sly]

declare @tb table (id int,[value] int)
insert into @tb select 1,20
insert into @tb select 2,20
insert into @tb select 3,25
insert into @tb select 4,25
insert into @tb select 5,30
insert into @tb select 6,35
insert into @tb select 7,40

select min(value) from @tb a
where not exists(select 1 from @tb where  value=a.value group by value having count(1)>1)

[liangCK]

select top 1 value from (select value from @t group by value having count(*)=1) t

[dawugui]

create table tb(id  int,   value int)
insert into tb values(1,         20 )
insert into tb values(2,         20 )
insert into tb values(3,         25 )
insert into tb values(4,         25 )
insert into tb values(5,         30 )
insert into tb values(6,         35 )
insert into tb values(7,         40 )

select a.* from tb a where value in
(select top 1 value from tb group by value having count(*) = 1 order by value)

drop table tb

/*
id          value       
----------- ----------- 
5           30

（所影响的行数为 1 行）
*/

[-狙击手-]

create table tb(id  int,   value int)
insert into tb values(1,         20 )
insert into tb values(2,         20 )
insert into tb values(3,         25 )
insert into tb values(4,         25 )
insert into tb values(5,         30 )
insert into tb values(6,         35 )
insert into tb values(7,         40 )

select top 1 *  
from tb a
where exists
(
  select value from tb where value = a.value group by value having count(*) = 1
)

drop table tb
/*
id          value       
----------- ----------- 
5           30

（所影响的行数为 1 行）

*/

[areswang]

declare @a table(id int,value int)
insert @a select 1,20
union all
select 2,20
union all
select 3,25
union all
select 4,25
union all
select 5,30
union all
select 6,35
union all
select 7,40
select * from @a

select min(a.value)
from (select value from @a group by value having count(1) = 1)a
------------
30