-- https://docs.oracle.com/en/database/oracle/oracle-database/23/lnpls/plsql-control-statements.html
CREATE OR REPLACE PROCEDURE print_grade (
  grade CHAR
) AUTHID DEFINER AS
BEGIN
  CASE grade
    WHEN 'A' THEN DBMS_OUTPUT.PUT_LINE('Excellent');
    WHEN 'B' THEN DBMS_OUTPUT.PUT_LINE('Very Good');
    WHEN 'C' THEN DBMS_OUTPUT.PUT_LINE('Good');
    WHEN 'D' THEN DBMS_OUTPUT.PUT_LINE('Fair');
    WHEN 'F' THEN DBMS_OUTPUT.PUT_LINE('Poor');
    ELSE NULL;
  END CASE;
END;
/
BEGIN
  print_grade('A');
  print_grade('S');
END;
/