? DATEDIFF() Function in SQL

The DATEDIFF() function calculates the difference between two dates and returns the result as an integer.

? Syntax Variations

• SQL Server:

DATEDIFF(datepart, start_date, end_date)

• MySQL:

DATEDIFF(end_date, start_date)

• PostgreSQL:

No direct DATEDIFF() function, but you can subtract dates:

end_date - start_date

? Parameters

? Examples

SQL Server — Difference in days between two dates

SELECT DATEDIFF(day, '2025-06-01', '2025-06-06') AS DaysDifference;-- Result: 5

SQL Server — Difference in months

SELECT DATEDIFF(month, '2025-01-01', '2025-06-01') AS MonthsDifference;-- Result: 5

MySQL — Difference in days

SELECT DATEDIFF('2025-06-06', '2025-06-01') AS DaysDifference;-- Result: 5

PostgreSQL — Difference in days (using subtraction)

SELECT '2025-06-06'::date - '2025-06-01'::date AS DaysDifference;-- Result: 5

? Notes

• SQL Server’s DATEDIFF supports many datepart values like year, month, day, hour, minute, etc.

• MySQL’s DATEDIFF only returns the difference in days.

• In PostgreSQL, subtracting dates returns an integer number of days.

If you want examples for a specific SQL dialect or for other units like hours or minutes, just ask!