regex - Checking for a pure string using regexp_like -

i need check "substring of first 6 characters" of input string pure string.

declare p_str varchar2(30) := 'abcd1240'; l_result varchar2(20);  begin if regexp_like(substr(p_str,1,6), '[[:alpha:]]')         dbms_output.put_line('it pure string'); else         dbms_output.put_line('it alphanumeric'); end if;  end; / 

i can see first 6 characters of string abcd1290 alphanumeric contains 12. but, output printed says otherwise.

am doing wrong "alpha" in regexp_like ? thought alpha supposed pure characters , not numbers. here, abcd1290 should give me: alphanumeric output. abcdxy90 should : pure string

try this:

declare   l_res varchar2(100); begin   in (select 'abcdef123' val dual union              select '123abc123' dual union             select '123456abc' dual)   loop     if regexp_like(i.val, '^\d{6}')           l_res := 'alpha';     else       l_res := 'numeric';     end if;     dbms_output.put_line(i.val || ' ' || l_res);   end loop; end;  123456abc numeric 123abc123 numeric abcdef123 alpha