求一 SQL语句
表test,字段id1是唯一的,数据如下：
id         id1
1             1
2             2
2             3
2             4
3             5
3             6

用一条语句取出id不重复的记录,应该怎么写?

------解决方案--------------------
select * from test a
where not exists(select * from test where id=a.id and id1 <> a.id1)
------解决方案--------------------
select id,max(id1) from test group by id
------解决方案--------------------
select id,max(id1) from test group by id having count(*)=1
------解决方案--------------------
id id1

表名:ta
select * from ta as a
where (select count(*) from ta where id=a.id)!> 1