sql生成20位数随机数

declare @rnd nvarchar(50)
set @rnd =''
while LEN(@rnd)<20
begin
set @rnd =@rnd + REPLACE ( CONVERT(nvarchar, RAND ()),'0.','')
while LEFT(@rnd,1)='0'
set @rnd = RIGHT (@rnd,len(@rnd)-1)
end
set @rnd=LEFT(@rnd ,20)
select @rnd