我无法在oracle中打印以下金字塔。（PL/SQL块）

比以前的答案短一些的代码：

SQL> select substr('ORACLE', 1, level) val
  2  from dual
  3  connect by level <= length('ORACLE')
  4  order by level desc;

VAL
------------------------
ORACLE
ORACL
ORAC
ORA
OR
O

6 rows selected.

SQL>