--> 测试数据：[test]
if object_id('[test]') is not null drop table [test]
create table [test]([字段A] varchar(1),[字段B] varchar(4),[字段C] int)
insert [test]
select 'A','结束',3 union all
select 'A','开始',2 union all
select 'A','开始',1 union all
select 'B','结束',7 union all
select 'B','开始',6 union all
select 'B','开始',5 union all
select 'B','开始',4 union all
select 'B','开始',3 union all
select 'B','开始',2 union all
select 'B','开始',1 union all
select 'C','开始',2 union all
select 'C','开始',1 union all
select 'D','开始',3 union all
select 'D','开始',2 union all
select 'D','开始',1


select [字段A],[字段B],MAX([字段C]) as [字段C]
from test
where [字段A] not in(
select [字段A] from test where [字段B]='结束'
)
group by [字段A],[字段B]

/*

字段A    字段B    字段C
C    开始    2
D    开始    3*/