Generate a Pyramid

You have table pyramid_table with 2 columns CH and NUM. It contains 1 row. The column CH contains a single character and column NUM contains a number.

Write a SQL query to Generate a pyramid of CH characters of height NUM e.g if CH is '*' and NUM is 5, the output should be :

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

Solution:

SELECT
lpad(' ',num-rownum,' ')||substr(lpad(ch,2*num,ch),1,2*rownum-1)||lpad(' ',num-rownum,' ') as pyramid
from
pyramid_table,all_objects
where
rownum<=num