Date difference functions

Date difference functions calculate the number of days (or hours, months, or other units) between two dates.

About 5–10 minutes · no sign-up needed

Example

How many days between two dates

SELECT order_id, order_date, ship_date,
       ship_date - order_date AS days_to_ship
FROM orders

Result:

order_id	order_date	ship_date	days_to_ship
O2001	2024-03-01	2024-03-03	2
O2002	2024-03-05	2024-03-10	5
O2003	2024-03-07	2024-03-08	1

AS gives a column a friendlier name in the result.

SELECT order_id, ship_date - order_date AS days_to_ship

FROM tells SQL which table to pull the data from.

SELECT order_id, ship_date - order_date AS days_to_ship
FROM orders;

Try each one in your head first, then open the answer.

1. Using orders, write a query to find the number of days between today and order_date.

SELECT CURRENT_DATE - order_date FROM orders

2. Using shipments, write a query to find the number of days between today and ship_date.

SELECT CURRENT_DATE - ship_date FROM shipments

3. Using promotions, write a query to find the number of days between end_date and start_date.

SELECT end_date - start_date FROM promotions

4. Using store_sales, write a query to find the number of days between today and sale_date.

SELECT CURRENT_DATE - sale_date FROM store_sales

5. Using returns, write a query to find the number of days between today and return_date.

SELECT CURRENT_DATE - return_date FROM returns

Learn it by doing. This lesson is a short hands-on level on Bampaa: see it work, then build and write it yourself, with instant feedback.

About 5–10 minutes · no sign-up needed