SQL_试验

IF NOT EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[UserInfo]') AND type in (N'U'))
BEGIN
CREATE TABLE [dbo].[UserInfo](
 [UserID] [bigint] IDENTITY(999999999999999999,10000000) NOT NULL,
 [UserName] [varchar](50) NULL,
 [UserAddress] [varchar](50) NULL,
 [UserTimeStamp] [timestamp] NULL,
 [GUID] [uniqueidentifier] NULL,
 [DefaultValue] [varchar](50) NULL CONSTRAINT [DF_UserInfo_DefaultValue]  DEFAULT (newid()),
 CONSTRAINT [PK_UserInfo] PRIMARY KEY CLUSTERED
(
 [UserID] ASC
)WITH (PAD_INDEX  = OFF, IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY]
END
-------------------------------------------------------------------------------------------------------

declare @id int
set @id=1
while(@id<1000000)
begin

insert UserInfo (UserName,UserAddress,UserTimeStamp,GUID,DefaultValue) values('eee','eee',default,newid(),default);
set @id=@id+1
end

update UserInfo set UserAddress='bbbb' where UserID=2
select * from UserInfo order by USERID desc

insert UserInfo (UserName,UserAddress,UserTimeStamp,GUID,DefaultValue) values('eee','eee',default,newid(),default);
select * from UserInfo order by USERID desc

declare @val uniqueidentifier
select GUID from UserInfo where UserID=4
print len(convert(varchar(100),@val))

---------------------此语句可以测试  执行10000 次插入操作所要花费的时间  ------------------------------------
declare @id int
declare @timefirst datetime
declare @timeend datetime
begin
 set @timefirst=getdate()
 set @id=1
 while(@id<100000)
  begin
   insert UserInfo (UserName,UserAddress,UserTimeStamp,GUID,DefaultValue) values('eee','eee',default,newid(),default);
   set @id=@id+1
  end
set @timeend=getdate()
print 'StartTime:'+convert(varchar(30),@timefirst)
print 'EndTime:'+convert(varchar(30),@timeend)
print 'Operate Times:'+ convert(varchar(30),Datediff(millisecond,@timefirst,@timeend))
end

-----------------------SELECT 完整语法如下:-------------------------------
SELECT 查询列表
[INTO 新的表名]
FROM 需要查询数据的表
[WHERE 查询条件]
[GROUP BY 分组列表]
[HAVING 分组查询条件]
[ORDER BY 排序列表 [ASC|DESC]]