學習dump函式

 5,學習dump函式
          select dump('1') from dual
          union all
          select dump('我') from dual
          union all
          select dump('1我') from dual
          union all
          select dump('我') from dual
          union all
          select dump('a') from dual                   
 執行結果
            Typ=96 Len=1: 49
            Typ=96 Len=2: 206,210
            Typ=96 Len=3: 49,206,210
            Typ=96 Len=2: 206,210
            Typ=96 Len=1: 97
　
 小結：len表明位元組長度
       冒號後表明儲存的內容
       1我是３個位元組，因為我是2個位元組