SQL Server : How to test if a string has only digit characters

Question

I am working in SQL Server 2008. I am trying to test whether a string (varchar) has only digit characters (0-9). I know that the IS_NUMERIC function can give spurious results.

Answer 1

Method that will work. The way it is used above will not work.

declare @str varchar(50)='79136'

select 
  case 
    when  @str LIKE replicate('[0-9]',LEN(@str)) then 1 
    else 0 
  end

declare @str2 varchar(50)='79D136'

select 
  case 
    when  @str2 LIKE replicate('[0-9]',LEN(@str)) then 1 
    else 0 
  end