# What Data Type Is Datediff?

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Angela Bailey

What Data Type Is Datediff?

When working with dates in programming, it is often necessary to calculate the difference between two dates. In SQL, the `DATEDIFF` function provides a convenient way to accomplish this task. But have you ever wondered what data type the `DATEDIFF` function returns?

## DateDiff Function

The `DATEDIFF` function calculates the difference between two dates and returns an integer value that represents the number of date or time intervals between the specified start date and end date. It takes three arguments:

• Datepart: Specifies the unit of measurement for the difference calculation. Some commonly used values include year, month, day, hour, minute, second.
• Startdate: The starting date from which to calculate the difference.
• Enddate: The ending date until which to calculate the difference.

The syntax for using the `DATEDIFF` function is as follows:

``````DATEDIFF(datepart, startdate, enddate)
``````

## Data Type Returned by Datediff Function

The data type returned by the `DATEDIFF` function is always an integer. This means that regardless of the unit of measurement specified in the `Datepart` argument, such as year or month, the result will be rounded down to a whole number.

This behavior is important to keep in mind when working with fractional units like hours or minutes. If you need a more precise result with decimal places, you may need to use other functions or perform additional calculations.

## Example

Let’s take a look at an example to understand the data type returned by the `DATEDIFF` function:

``````SELECT DATEDIFF(YEAR, '2010-01-01', '2020-12-31') AS YearDifference;
``````

In this example, we are calculating the difference in years between the start date ‘2010-01-01’ and the end date ‘2020-12-31’. The result will be an integer value representing the number of whole years between these two dates.

### Conclusion

The `DATEDIFF` function is a useful tool for calculating date differences in SQL. It returns an integer data type that represents the number of intervals between two dates. Remember that it always rounds down to a whole number, so if you need more precision, you may need to use alternative approaches or perform additional calculations.

Now that you have a clear understanding of what data type the `DATEDIFF` function returns, you can confidently use it in your SQL queries to calculate date differences accurately.