查询SQL或PL/SQL中给定N值的三角形星号(星号)

Question

我正在SQL或PL/SQL中开发一个查询，如下所示。我尝试了以下查询

SELECT     RPAD ('* ', LEVEL*2, '* ')
 FROM DUAL
CONNECT BY LEVEL <= 5 
UNION all
SELECT   RPAD ('* ', LEVEL*2, '* ')
 FROM DUAL
CONNECT BY LEVEL <= 5;

但是我得到的输出是这种形式的。

* 
* * 
* * * 
* * * * 
* * * * * 
* 
* * 
* * * 
* * * * 
* * * * * 

，但我需要的输出格式是

* 
* * 
* * * 
* * * * 
* * * * *
* * * * 
* * * 
* * 
*

有人能帮我做这件事吗。

Answer 1

这个怎么样：

SELECT     RPAD ('* ', LEVEL*2, '* ')
FROM       DUAL
CONNECT BY LEVEL <= 5 
UNION all
SELECT   RPAD ('* ', (5-LEVEL)*2, '* ')
FROM DUAL
CONNECT BY LEVEL <= 5;

Answer 2

我觉得这是对的。

SELECT     RPAD (' ', LEVEL*2, ' ')
FROM       DUAL
CONNECT BY LEVEL <= 5 
UNION all
SELECT   RPAD (' ', (5-LEVEL)*2, ' ')
FROM DUAL
CONNECT BY LEVEL <= 5-1;

希望它能帮你…！！