Writing a Recursive PostgreSQL Function for Factorial Calculation

Function to Calculate Factorial of a Number

Write a PostgreSQL function to calculate the factorial of a given integer.

Solution:

-- Create a function named factorial that takes an integer as input and returns a big integer
CREATE FUNCTION factorial(n INT) RETURNS BIGINT AS $$
BEGIN
    -- Base case: if n is 0, return 1
    IF n = 0 THEN
        RETURN 1;
    ELSE
        -- Recursive case: return n multiplied by the factorial of (n - 1)
        RETURN n * factorial(n - 1);
    END IF;
END;
-- Specify the language used in the function as PL/pgSQL
$$ LANGUAGE plpgsql;

Explanation:

• Purpose of the Query:
• Calculates the factorial of a given number recursively.
• Key Components:
• Uses recursion to compute factorial values
• Real-World Application:
• Used in probability theory, statistical models, and computing permutations.

For more Practice: Solve these Related Problems:

• Write a PostgreSQL function to calculate the sum of all numbers from 1 to N.
• Write a PostgreSQL function to compute the Fibonacci sequence up to a given number.
• Write a PostgreSQL function that finds the factorial of a number using a loop instead of recursion.
• Write a PostgreSQL function that calculates the factorial but returns NULL if the input is negative.

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