PL SQL - Factorial Value

Factorial

In mathematics, the factorial of a non-negative integer n, denoted by n!, is the product of all positive integers less than or equal to n.

For example,

${\displaystyle 5!=5\times 4\times 3\times 2\times 1=120.}$

So it's easy to find the factorial value for the small integers. But for high value numbers?
Calculators? How long it will take?

Solution: We can use Computer Programming Language to find the factorial value within Nano Seconds. And here is the PL/SQL Program to find out the factorial values for 10 positive integers.

PL/SQL

Procedure

SQL> CREATE OR REPLACE FUNCTION Factorial(fact INTEGER)
  2  RETURN NUMBER AS
  3  BEGIN
  4       IF fact = 1 THEN
  5            RETURN 1;
  6       ELSE
  7            RETURN(fact * Factorial(fact-1));
  8       END IF;
  9  END;
 10  /

Function created.

SQL> DECLARE
  2       n NUMBER := 10;
  3       i INTEGER ;
  4  BEGIN
  5       FOR i IN 1..n LOOP
  6            DBMS_OUTPUT.PUT_LINE('The factorial of' ||
  7                 i || 'is' || Factorial(fact));
  8       END LOOP;
  9  END;
 10  /

Output

The factorial of 1 is 1
The factorial of 2 is 2
The factorial of 3 is 6
The factorial of 4 is 24
The factorial of 5 is 120
The factorial of 6 is 720
The factorial of 7 is 5040
The factorial of 8 is 40320
The factorial of 9 is 362880
The factorial of 10 is 3628800

PL/SQL procedure successfully completed.

I used function here. You can also try without function.

SQL> DECLARE
  1       i NUMBER;
  2       fact NUMBER:=1;
  3       n NUMBER;
  4   BEGIN
  5        n:=&n;
  6        FOR i IN 1..n
  7      LOOP
  8         fact:=fact*i;
  9      END LOOP;
 10          DBMS_OUTPUT.ENABLE;
 11          DBMS_OUTPUT.PUT_LINE('The factorial value of' ||
                  n|| 'is' ||fact);
 12   END;
 13    /