# DateDifferenceDays (DateTime)

| **Name**    | ***DateDifferenceDays***                                                                                                                                  |
| ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Syntax      | DateDifferenceDays (Date leftDate, Date rightDate)                                                                                                        |
| Purpose     | To compute the difference between the specified dates in days.                                                                                            |
| Description | Subtracts a date time value from another date time value and returns result in days.                                                                      |
| 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\(200\).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(200).png" alt=""><figcaption></figcaption></figure>

In the output window, you can see that the provided datetime values have been subtracted, and the output has been displayed in the form of days.

![](https://github.com/astera-software/Astera_Data_Stack_v9/blob/main/.gitbook/assets/2%20\(198\).png)