SQL Server 2008中SQL之WaitFor-在规定时间执行操作

    

 

 

在SQL Server 2005以上版本中，在一个增强的WaitFor命令，其作用可以和一个job相当。但使用更加简捷。

看MSDN:
http://msdn.microsoft.com/zh-cn/library/ms187331.aspx
语法为：

[ruby] view plaincopyprint?

1. WAITFOR
2. {
3. DELAY 'time_to_pass'
4. | TIME 'time_to_execute'
5. | [ ( receive_statement ) | ( get_conversation_group_statement ) ]
6. [ , TIMEOUT timeout ]
7. }

WAITFOR{ DELAY 'time_to_pass' | TIME 'time_to_execute' | [ ( receive_statement ) | ( get_conversation_group_statement ) ] [ , TIMEOUT timeout ]}

以下示例在晚上 10:20 (22:20 ) 执行存储过程 sp_update_job 。

[ruby] view plaincopyprint?

1. USE msdb;
2. EXECUTE sp_add_job @job_name ='TestJob';
3. BEGIN
4. WAITFOR TIME '22:20';
5. EXECUTE sp_update_job @job_name ='TestJob',
6. @new_name ='UpdatedJob';
7. END;
8. GO

USE msdb;EXECUTE sp_add_job @job_name = 'TestJob';BEGIN WAITFOR TIME '22:20'; EXECUTE sp_update_job @job_name = 'TestJob', @new_name = 'UpdatedJob';END;GO

以下示例在两小时的延迟后执行存储过程。注意:Delay最多不超过24小时

[ruby] view plaincopyprint?

1. BEGIN
2. WAITFOR DELAY '02:00';
3. EXECUTE sp_helpdb;
4. END;
5. GO
6. 以下示例显示如何对 WAITFOR DELAY选项使用局部变量。将创建一个存储过程，该过程将等待可变的时间段，然后将经过的小时、分钟和秒数信息返回给用户。
7. USE AdventureWorks2008R2;
8. GO
9. IF OBJECT_ID('dbo.TimeDelay_hh_mm_ss','P') IS NOT NULL
10. DROP PROCEDURE dbo.TimeDelay_hh_mm_ss;
11. GO
12. CREATE PROCEDURE dbo.TimeDelay_hh_mm_ss
13. (
14. @DelayLength char(8)='00:00:00'
15. )
16. AS
17. DECLARE @ReturnInfo varchar(255)
18. IF ISDATE('2000-01-01 ' +@DelayLength +'.000') = 0
19. BEGIN
20. SELECT @ReturnInfo ='Invalid time ' +@DelayLength
21. + ',hh:mm:ss, submitted.';
22. -- This PRINT statement is for testing,not usein production.
23. PRINT @ReturnInfo
24. RETURN(1)
25. END
26. BEGIN
27. WAITFOR DELAY @DelayLength
28. SELECT @ReturnInfo ='A total time of ' +@DelayLength + ',
29. hh:mm:ss, has elapsed! Your time is up.'
30. -- This PRINT statement is for testing,not usein production.
31. PRINT @ReturnInfo;
32. END;
33. GO
34. /* This statement executes the dbo.TimeDelay_hh_mm_ss procedure. */
35. EXEC TimeDelay_hh_mm_ss '00:00:10';
36. GO

BEGIN WAITFOR DELAY '02:00'; EXECUTE sp_helpdb;END;GO以下示例显示如何对 WAITFOR DELAY选项使用局部变量。将创建一个存储过程，该过程将等待可变的时间段，然后将经过的小时、分钟和秒数信息返回给用户。USE AdventureWorks2008R2;GOIF OBJECT_ID('dbo.TimeDelay_hh_mm_ss','P') IS NOT NULL DROP PROCEDURE dbo.TimeDelay_hh_mm_ss;GOCREATE PROCEDURE dbo.TimeDelay_hh_mm_ss ( @DelayLength char(8)= '00:00:00' )ASDECLARE @ReturnInfo varchar(255)IF ISDATE('2000-01-01 ' + @DelayLength + '.000') = 0 BEGIN SELECT @ReturnInfo = 'Invalid time ' + @DelayLength + ',hh:mm:ss, submitted.'; -- This PRINT statement is for testing, not use in production. PRINT @ReturnInfo RETURN(1) ENDBEGIN WAITFOR DELAY @DelayLength SELECT @ReturnInfo = 'A total time of ' + @DelayLength + ', hh:mm:ss, has elapsed! Your time is up.' -- This PRINT statement is for testing, not use in production. PRINT @ReturnInfo;END;GO/* This statement executes the dbo.TimeDelay_hh_mm_ss procedure. */EXEC TimeDelay_hh_mm_ss '00:00:10';GO


执行结果：

A total time of 00:00:10, in hh:mm:ss, has elapsed.Your time is up.

小结：这是一种轻巧的解决方案。当你没有权限指定job时，可以考虑用WaitFor语句。

邀月注：本文版权由邀月和CSDN共同所有，转载请注明出处。
助人等于自助! [e-mail]