Oracle case,if

DECLARE
 
  V_CASE       VARCHAR2(100) := 'CASE';
  V_IF         VARCHAR2(100) := 'IF';
  V_PRINT_CASE VARCHAR2(100);
  V_PRINT_IF   VARCHAR2(100);
  V_OTHER      VARCHAR2(50) := 'OTHER';
 
BEGIN
 
  CASE
    WHEN V_CASE = 'CASE' THEN
      V_PRINT_CASE := 'CASE';
    
    WHEN V_CASE = '789' THEN
      V_PRINT_CASE := '789';
    
    ELSE
      V_PRINT_CASE := 'CASE ELSE';
    
  END CASE;
 
  CASE V_CASE
    WHEN 'CASE' THEN
      V_PRINT_CASE := 'CASE';
    
  END CASE;
 
  IF V_IF = 'IF' THEN
    V_PRINT_IF := 'IF';
  
  ELSIF V_IF = '6' THEN
    V_PRINT_IF := '6';
  END IF;
 
  IF V_IF = 'IF' THEN
    V_PRINT_IF := 'IF';
  END IF;
 
  DBMS_OUTPUT.put_line(V_PRINT_CASE);
  DBMS_OUTPUT.put_line(V_PRINT_IF);
 
  --SELECT * FROM (SELECT A1 FROM TEST UNION ALL SELECT CT1 FROM TEST2);
  --结果：
   /* A1
  r1c1
  r2c1
  r3c1
  r4c1_2
  r1c1*/
 
END;