sql server里将十六进制转换成十进制

在网上找了很多，总是不知道怎么用，于是自己写了一个：
declare @strHex char(5),
@len int,
@intOut int,
@i int,
@charint int
set @strHex = '20'
set @len = len(rtrim(@strHex))
set @i = 1
set @intOut = 0
while @i <= @len
begin
set @charint = case substring(upper(rtrim(ltrim(@strHex))),@i,1)
when 'A' then 10
when 'B' then 11
when 'C' then 12
when 'D' then 13
when 'E' then 14
when 'F' then 15
else substring(@strHex,@i,1)
end
set @intOut = @intOut +@charint * power(16, @len-@i)
set @i = @i + 1
end
print @intOut 
由于要批量修改，帮写成了游标的形式：
use pubs
declare @strHex char(5),
@len int,
@intOut int,
@i int,
@charint int,
@keyname char(50)
declare hextoint cursor for
select rtrim(col001),rtrim(col002) from vv
open hextoint
fetch next from hextoint into @keyname,@strHex
while @@fetch_status =0
begin
set @len = len(rtrim(@strHex))
set @i = 1
set @intOut = 0
while @i <= @len
begin
set @charint = case substring(upper(rtrim(ltrim(@strHex))),@i,1)
when 'A' then 10
when 'B' then 11
when 'C' then 12
when 'D' then 13
when 'E' then 14
when 'F' then 15
else substring(@strHex,@i,1)
end
set @intOut = @intOut +@charint * power(16, @len-@i)
set @i = @i + 1
end
update vv set col002 = @intout where col001 = rtrim(@keyname)
--print @intOut
fetch next from hextoint into @keyname,@strHex
end
close hextoint
deallocate hextoint 
记以下留作以后参考吧。