一些SQL语句
-------创建临时存储过程create proc #pr_xxx
as
select 'fff'
exec #pr_xxx --执行存储过程
-------扩展存储过程
exec xp_cmdshell 'dir c:\'
可执行DOS的命令，如删除，创建，复制等等
------存储过程实例一(加法运算)
create procedure pr_sss
@n1 smallint,
@n2 smallint,
@sum smallint output
as
set @sum=@n1+@n2
return 10
go
declare @sss smallint,@ddd int
exec @ddd=pr_sss 20,10,@sss output
print @ddd
print @sss
------存储过程实例二(pr_helptext)
create procedure pr_helptext --修改用alter
@arg1 varchar(100)
as
select text from syscomments where object_id(@arg1)=id
go
exec pr_helptext pr_sss
------存储过程实例三
create procedure pr_ksk
as
insert into ssss_bak
select * from ssss
exec pr_ksk
------自动备份数据库(with init是重写)
declare @path varchar(100)
set @path=convert(varchar(10),getdate(),120)
set @path='d:\bak1\'+@path+'.bak'
backup database shidian to disk=@path with init
------自动删除备份(前5天)
declare @path varchar(100)
set @path=convert(varchar(10),getdate()-5,120)
set @path=' del d:\bak1\'+@path+'.bak'
exec master.dbo.xp_cmdshell @path
-------自动备份删除文件(前5天)
declare @path varchar(100)
set @path=convert(varchar(10),getdate(),120)
set @path='d:\bak1\'+@path+'.bak'
print @path
backup database shidian to disk=@path with INIT
set @path=convert(varchar(10),getdate()-5,120)
set @path='del d:\bak1\'+@path+'.bak'
print @path
EXEC master.dbo.xp_cmdshell @path
使用加法运算符将天数加到日期和时间值中
下面的示例将若干天数加到 datetime 日期上。
SELECT DATEDIFF(mi, CONVERT(datetime,'11:00:00'),CONVERT(datetime,'13:30:00'))/60.0
SELECT DATEDIFF(MINUTE,'2002-1-1 11:00:00','2002-1-1 13:30:00') / 60 + CASE WHEN DATEDIFF(minute,'2002-1-1 11:00:00','2002-1-1 13:30:00') % 60 >=30 THEN 0.5 ELSE 0 END
DECLARE @startdate datetime, @adddays int
SET @startdate = '1/10/1900 12:00 AM'
SET @adddays = 5
SET NOCOUNT OFF
SELECT @startdate + 1.25 AS 'Start Date',
@startdate + @adddays AS 'Add Date'
下面是结果集：
Start Date Add Date
--------------------------- ---------------------------
Jan 11 1900 6:00AM Jan 15 1900 12:00AM