求助:如何在SQL语句取得某char类型字段中字符'.'的个数!

create function getnum(@code varchar(200))
returns int
as
begin
declare @i int
set @i=0
   while charindex('.',@code)>0
   begin
     set @code=substring(@code,charindex('.',@code)+1,8000)
     set @i=@i+1
   end
return @i
end语句:
select id,code,dbo.getnum(code) as P_NUM from tablename