Calculate Days Between Two Dates using a PostgreSQL Function

Function to Get the Number of Days Between Two Dates

Write a PostgreSQL function that calculates the number of days between two given dates.

Solution:

-- Create a function named days_between that takes two dates as input and returns an integer
CREATE FUNCTION days_between(start_date DATE, end_date DATE) RETURNS INT AS $$
BEGIN
    -- Calculate the difference in days between the end_date and start_date
    RETURN end_date - start_date;
END;
-- Specify the language used in the function as PL/pgSQL
$$ LANGUAGE plpgsql;

Explanation:

• Purpose of the Query:
• Calculates the difference in days between two dates.
• Real-World Application:
• Used in event planning, payroll processing, and analytics.

For more Practice: Solve these Related Problems:

• Write a PostgreSQL function that calculates the number of weekdays between two given dates.
• Write a PostgreSQL function that calculates the number of months between two given dates.
• Write a PostgreSQL function that finds how many days have passed since January 1, 2000.
• Write a PostgreSQL function that determines if a given date falls on a weekend.

Go to:

• Comprehensive Guide to writing PL/pgSQL Functions in PostgreSQL Exercises Home. ↩
• PostgreSQL Exercises Home ↩

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