如何在SQL数据表中如何剔除连续重复的记录,统计个数时只记做1条记录?

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如何剔除数据表中连续重复的记录记做1条记录??
数据表如下,我想要取result=0的sn在各prodorderid下的个数( 注意:要剔除连续重复的数据,记做1条记录,但是不连续的重复的分别记为1条记录

create table test 

(
id int identity(1,1) primary key,
sn varchar(50) not null,
prodorderid int not null,
result int not null
)
--insert into test values ('20140425001',1,0)
--insert into test values ('20140425001',1,1)
--insert into test values ('20140425001',2,0)
--insert into test values ('20140425001',2,0)
--insert into test values ('20140425001',2,0)
--insert into test values ('20140425001',1,1)
--insert into test values ('20140425001',2,0)
--insert into test values ('20140425001',2,0)
--insert into test values ('20140425001',2,1)
--insert into test values ('20140425001',3,0)
--insert into test values ('20140425001',1,1)
--insert into test values ('20140425001',2,0)
--insert into test values ('20140425001',2,0)
--insert into test values ('20140425001',1,0)
--insert into test values ('20140425001',1,0)

具体问题如图片所示:
CSDN移动问答

select prodorderid ,count(sn) from test where result = 0 group by prodorderid