IF OBJECT_ID('tb') IS NOT NULL
    DROP TABLE tb;
GO
CREATE TABLE tb(id int, mid int, starttime datetime);
INSERT INTO tb(id, starttime)
select  1, '2012-04-01 08:00:00' union all
select  1, '2012-04-01 15:20:00' union all
select  1, '2012-04-02 00:50:00' union all
select  1, '2012-04-02 8:50:00' union all
select  1, '2012-04-02 18:50:00' union all
select  1, '2012-04-03 5:50:00' union all
select  2, '2012-04-04 5:50:00' union all
select  2, '2012-04-04 8:50:00' union all
select  2, '2012-04-04 15:50:00';

--select id, starttime from tb;

select a.id, sum([count]) as 次数
from (  select id, max(num) as [Count] 
        from (
                select a.id, a.starttime, 1 as num
                from tb a 
                where a.starttime >= '2012-04-01' and a.starttime <= '2012-04-12'
                    and convert(varchar(8), a.starttime, 108) between '05:30:00' and '14:30:00'
                    and (exists (    select 1 from tb b 
                                    where a.id = b.id  
                                        and b.starttime between cast( convert(varchar(10), a.starttime, 120) + ' 05:30:00' as datetime)  
                                                            and cast( convert(varchar(10), a.starttime, 120) + ' 14:30:00' as datetime)  
                                )
                        )
                    and (exists (    select 1 from tb b1 
                                    where a.id = b1.id  
                                    and b1.starttime > cast( convert(varchar(10), a.starttime, 120) + ' 14:30:00' as datetime) 
                                    and b1.starttime <= cast( convert(varchar(10), a.starttime + 1, 120) + ' 14:30:00' as datetime) 
                                )
                        )  
               ) t
        group by id, convert(varchar(10), starttime, 120)
     ) a
group by a.id