> For the complete documentation index, see [llms.txt](https://documentation.astera.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://documentation.astera.com/astera-data-stack-v6/functions/date-time/datedifferenceyears-datetime.md).

# DateDifferenceYears (DateTime)

| **Name**    | ***DateDifferenceYears***                                                                                                                                 |
| ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Syntax      | DateDifferenceYears (Date leftDate, Date rightDate)                                                                                                       |
| Purpose     | To compute the difference between the specified dates in years.                                                                                           |
| Description | Subtracts a date time value from another date time value and returns result in years by dividing number of days by 365.2425.                              |
| Return Type | Double                                                                                                                                                    |
| Parameters  | <p>leftDate \[System.DateTime] – Date from which the other date will be subtracted</p><p>rightDate \[System.DateTime] – Date which will be subtracted</p> |

![](https://github.com/astera-software/Astera_Data_Stack_v9/blob/main/.gitbook/assets/0%20\(172\).png)

**Example**

In this example, we will pass date time values to be subtracted to the function transformation object using a *Variables* object.

Where,

*leftDate* = 01/01/2023

*rightDate* = 01/02/2022

<figure><img src="https://github.com/astera-software/Astera_Data_Stack_v9/blob/main/.gitbook/assets/1%20(172).png" alt=""><figcaption></figcaption></figure>

In the output window, you can see that the difference between the provided datetime values has been displayed in the form of years.

![](https://github.com/astera-software/Astera_Data_Stack_v9/blob/main/.gitbook/assets/2%20\(173\).png)


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