求其中同一個主叫號碼的兩次通話之間間隔大於10秒的通話記錄ID
求其中同一個主叫號碼的兩次通話之間間隔大於10秒的通話記錄ID
例如:6,7,8,9,10條記錄均符合
ID 主叫號碼 被叫號碼 通話起始時間 通話結束時間 通話時長
1 98290000 0215466546656 2007-02-01 09:49:53.000 2007-02-01 09:50:16.000 23
2 98290000 021546654666 2007-02-01 09:50:29.000 2007-02-01 09:50:41.000 12
3 98290000 021546654666 2007-02-01 09:50:58.000 2007-02-01 09:51:12.000 14
4 68290900 0755133329866 2007-02-01 10:04:31.000 2007-02-01 10:07:13.000 162
5 78290000 0755255708638 2007-02-01 10:48:26.000 2007-02-01 10:49:23.000 57
6 78290000 0755821119109 2007-02-01 10:49:39.000 2007-02-01 10:52:55.000 196
7 78290000 035730928370 2007-02-01 11:30:45.000 2007-02-01 11:31:58.000 73
8 78290000 0871138889904 2007-02-01 11:33:47.000 2007-02-01 11:35:00.000 73
9 68290000 035730928379 2007-02-01 11:52:20.000 2007-02-01 11:54:56.000 156
10 68290000 0298521811199 2007-02-01 12:44:45.000 2007-02-01 12:45:04.000 19
將資料複製到記事本,儲存為time.txt,匯入到資料庫,生成表[time],然後可做測試。得到三個方法:
--方法一
select distinct * from(
SELECT a.* FROM dbo.[time] a left join dbo.[time] b
ON a.phone=b.phone
WHERE a.id<b.id
AND DATEDIFF(second,a.st,b.et)>10
UNION ALL
SELECT a.* FROM dbo.[time] a left join dbo.[time] b
ON a.phone=b.phone
WHERE a.id>b.id
AND DATEDIFF(second,b.st,a.et)>10) a
order by id,phone
--方法二
SELECT
distinct
a.* FROM dbo.[time] a left join dbo.[time] b
ON a.phone=b.phone
WHERE a.id<>b.id
AND (DATEDIFF(second,a.st,b.et)>10 or DATEDIFF(second,b.st,a.et)>10)
order by id,phone
--方法三
select * from dbo.[time] t
where exists(select 1 from dbo.[time] where id<>t.id
and phone=t.phone
AND (DATEDIFF(second,st,t.et)>10 or DATEDIFF(second,t.st,et)>10))
我最喜歡方法三,採用exists語句。網上的許多SQL面試答案,通常用IN之類,極少用EXISTS,可能是習慣問題。
這道面試題,是從網上一篇文章裡抄過來,作者給出的答案是:
SELECT DISTINCT a.* FROM dbo.hc a left join dbo.hc b
ON a.主叫號碼=b.主叫號碼
WHERE a.id<>b.id AND (DATEDIFF(second,a.通話起始時間,b.通話結束時間)>10 AND
DATEDIFF(second,b.通話起始時間,a.通話結束時間)>10)
我覺得在這裡用 AND 是有問題的。
參考文章:
http://blog.sina.com.cn/s/blog_63041bb80101a8mn.html