sql生成随机字符串

--1、借助newid() 
go 
--创建视图(因为在函数中无法直接使用newid()) 
create view vnewid 
as 
select newid() N'MacoId'; 
go 
--创建函数 
create function getrandstr(@n int) 
returns varchar(max) 
as 
begin 
declare @i int 
set @i=ceiling(@n/32.00) 
declare @j int 
set @j=0 
declare @k varchar(max) 
set @k='' 
while @j<@i 
begin 
select @k=@k+replace(cast(MacoId as varchar(36)),'-','') from vnewid 
set @j=@j+1 
end 
set @k=substring(@k,1,@n) 
return @k 
end 

--测试示例 
select dbo.getrandstr(75) 
--运行结果 
/* 
D185504AD09C4D5796F7016983E67414CEE25162EA9F43D195D43328A4CF01AC7C586521D8E 
*/ 

--我们可以发现结果中的字母都是大写的，或是都是小写的。 
--换种方法来写下： 
go 
--创建函数 
create function [dbo].[m_rand](@mycount int) 
returns nvarchar(2000) 
as 
begin 
declare @maco_wang table (id varchar(1)) 
declare @maco_number int,@number int; 
declare @my_one nvarchar(max),@my_two nvarchar(max) 
set @my_one='';set @maco_number=0; set @number =48; 
while (@number>=48 and @number<=57) or (@number>=65 and @number<=90) or (@number>=97 and @number<=122) 
begin 
insert into @maco_wang select char(@number) 
set @number=@number+1; 
if(@number=58) 
begin 
set @number=65 
end 
if(@number=91) 
begin 
set @number=97 
end 
end 
while @maco_number<@mycount 
begin 
select @my_two=id from @maco_wang 
order by (select MacoId from dbo.vnewid ); 
set @my_one=@my_two+@my_one; 
set @maco_number=@maco_number+1; 
end 
return @my_one 
end 
--测试用例 
select [dbo].[m_rand](75) 
--运行结果 
/* 
5nN0w4o4VOkjacB5so2uvCuw2ZRrnBhxEi4IcsEOHzBbStKmR1p8ASH4N4XaxhDoDEtkX8bZ0CR 
*/

declare 
@i int
set @i=1
while @i <=100000
begin
insert into tbl_A select [dbo].[m_rand](5)
set @i=@i+1
end

 update tbl_C set UserPass=tbl_D.UserName from tbl_C,tbl_D where tbl_D.UserName=tbl_C.UserName