比较难的sql面试题，令我比较郁闷！

CREATE  TABLE  通话(id int ,主叫号码 varchar(8),被叫号码  varchar(30),通话起始时间 datetime ,通话结束时间 datetime,通话时长 int) 

INSERT  INTO 通话

select 1 , '98290000','0215466546656','2007-02-01 09:49:53.000', '2007-02-01 09:50:16.000',23   union
select 2, '98290000' ,'021546654666' ,'2007-02-01 09:50:29.000', '2007-02-01 09:50:41.000', 12  union
select 3, '98290000', '021546654666 ' ,'2007-02-01 09:50:58.000' ,'2007-02-01 09:51:12.000', 14  union
select 4, '68290900' ,'0755133329866', '2007-02-01 10:04:31.000', '2007-02-01 10:07:13.000' ,162  union
select 5,  '78290000' ,'0755255708638' ,'2007-02-01 10:48:26.000', '2007-02-01 10:49:23.000', 57  union
select 6, '78290000' ,'0755821119109', '2007-02-01 10:49:39.000' ,'2007-02-01 10:52:55.000' ,196  union
select 7, '78290000', '035730928370' , '2007-02-01 11:30:45.000', '2007-02-01 11:31:58.000', 73  union
select 8, '78290000', '0871138889904', '2007-02-01 11:33:47.000', '2007-02-01 11:35:00.000' ,73  union
select 9,  '68290000' ,'035730928379'  ,'2007-02-01 11:52:20.000', '2007-02-01 11:54:56.000' ,156  union
select 10 ,'68290000','0298521811199', '2007-02-01 12:44:45.000', '2007-02-01 12:45:04.000' ,19





SELECT   a.id 
from 通话 a, 通话 b 
where a.主叫号码=b.主叫号码  
and a.id!=b.id 
and   datediff(s,b.通话起始时间,a.通话起始时间)>10

UNION 
SELECT   b.id 
from 通话 a, 通话 b 
where a.主叫号码=b.主叫号码  
and a.id!=b.id 
and   datediff(s,a.通话起始时间,b.通话起始时间)>10