Back to list T-SQL How to Calculate the Difference Between Two Dates in T-SQL Database: T-SQL Operators:DATEDIFF Problem: You have two columns of the date type and you want to calculate the difference between them. Example: In the travel table, there are three columns: id, departure, and arrival. You'd like to calculate the difference between arrival and departure, or the number of days from arrival to departure inclusively. The travel table looks like this: iddeparturearrival 12018-03-252018-04-05 22019-09-122019-09-23 32018-07-142018-07-14 42018-01-052018-01-08 Solution: SELECT id, departure, arrival, DATEDIFF(day, departure, arrival) AS date_difference, DATEDIFF(day, departure, arrival) + 1 AS days_inclusive FROM travel; The result is: iddeparturearrivaldate_differencedays 12018-03-252018-04-051112 22019-09-122019-09-231112 32018-07-142018-07-1401 42018-01-052018-01-0834 Discussion: To find the difference between dates, use the DATEDIFF(datepart, startdate, enddate) function. The datepart argument defines the part of the date/datetime in which you'd like to express the difference. Its value can be year, quarter, month, day, minute, etc. In this example, you want to express the difference in days, so the first argument is day. The two other arguments are the date from which you start counting and the date when you stop counting – In this case, departure and arrival, respectively. In most cases, what you really want is the number of days from the first date to the second date inclusively. Then you need to add 1 day to the difference in days: DATEDIFF(day, departure, arrival) + 1. Recommended courses: SQL Basics in SQL Server Common Functions in SQL Server Data Types in SQL Recommended articles: How Often Employees Are Running Late for Work: SQL Datetime and Interval SQL Arithmetic Performing Calculations on Date- and Time-Related Values How to Get the First Day of the Week in SQL Server See also: How to Add Days to a Date in T-SQL How to Subtract 30 Days from a Date in T-SQL Tags: T-SQL Subscribe to our newsletter Join our weekly newsletter to be notified about the latest posts.