Find out if a string contains only ASCII characters

You can use TRANSLATE to do this. Basically, translate away all the ASCII printable characters (there aren't that many of them) and see what you have left.

Here is a query that does it:

WITH input ( p_string_to_test) AS ( SELECT 'This this string' FROM DUAL UNION ALLSELECT 'Test this ' || CHR(7) || ' string too!' FROM DUAL UNION ALLSELECT 'xxx' FROM DUAL)SELECT p_string_to_test,        case when translate(p_string_to_test,        chr(0) || q'[ !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~]',        chr(0)) is null then 'Yes' else 'No' END is_asciiFROM input;

+-------------------------+----------+|    P_STRING_TO_TEST     | IS_ASCII |+-------------------------+----------+| This this string        | Yes      || Test this  string too!  | No       || xxx                     | Yes      |+-------------------------+----------+

ASCII function with upper limit of 127 may be used :

declare    str nvarchar2(100) := '\xyz~*-=)(/&%+$#£>|"éß';    a   nvarchar2(1);    b   number := 0;begin    for i in 1..length(str)    loop                       a := substrc(str,i,1);      b := greatest(ascii(a),b);          end loop;    if b < 128 then       dbms_output.put_line('String is composed of Pure ASCII characters');    else     dbms_output.put_line('String has non-ASCII characters');          end if; end;

I think I will go for one of these two

IF CONVERT(str, 'US7ASCII') = str THEN    DBMS_OUTPUT.PUT_LINE('Pure ASCII');END IF;IF ASCIISTR(REPLACE(str, '\', '/')) = REPLACE(str, '\', '/') THEN    DBMS_OUTPUT.PUT_LINE('Pure ASCII');END IF;