--> 测试数据：[test]
if object_id('[test]') is not null drop table [test]
create table [test]([id] int,[ba] int,[zc] int,[name] varchar(4))
insert [test]
select 1,1111,1,'小明' union all
select 2,1111,2,'小明' union all
select 3,1111,3,'小明' union all
select 4,2222,1,'小丽' union all
select 5,2222,2,'小丽' union all
select 6,3333,1,'小红'

select * from test a
where a.zc=(select MIN(zc) from test b where a.ba=b.ba)
/*
id    ba    zc    name
--------------------------------
1    1111    1    小明
4    2222    1    小丽
6    3333    1    小红
*/

------解决方案--------------------

SQL code
select * from test t where not exists(select 1 from test whereba=t.ba  and zc<t.zc)

------解决方案--------------------

SQL code
select id,ba,zc,name from(
select px=ROW_NUMBER()over(partition by ba order by zc asc),
* from test--这个查询返回的是按照ba分组，zc递增排序
)t
where px=1--取出每个分组的排序为1(px=1)的数据