SQL中char和varchar的效率分析

CREATE TABLE [dbo].[testchar] (
[a] [int] IDENTITY (1, 1) NOT NULL ,
[b] [char] (200) COLLATE Chinese_PRC_CI_AS NULL
) ON [PRIMARY]
GO
CREATE TABLE [dbo].[testvarchar] (
[a] [int] IDENTITY (1, 1) NOT NULL ,
[b] [varchar] (200) COLLATE Chinese_PRC_CI_AS NULL
) ON [PRIMARY]
GO

--truncate table testvarchar

--truncate table testchar
declare @i as int

set @i=0

while @i<50000
begin
insert into testvarchar values(cast(@i as varchar(200)))

set @i=@i+1

if @i=50000

break
end
declare @i as int

set @i=0

while @i<50000
begin
insert into testchar values(cast(@i as char(200)))

set @i=@i+1

if @i=50000

break
end