查找出某表字段数据不为空

DECLARE 
CURSOR temp IS SELECT COLUMN_NAME FROM ALL_TAB_COLUMNS WHERE TABLE_NAME=Upper('TEST');
v_num NUMBER;
BEGIN
  FOR i IN temp 
  LOOP
    execute immediate 'SELECT Count(*) FROM test WHERE '||i.COLUMN_NAME||' IS NOT null' INTO v_num; 
    IF v_num<>0 THEN 
      Dbms_Output.put_line('==columns that have  data=='||i.COLUMN_NAME);
    END IF; 
    NULL; 
  END LOOP;
END;