# DateDiff () Function

**YouTube:** [How to Use the DateDiff () Function in Report Custom Columns?](https://www.youtube.com/watch?v=SXu7wbNw8VU)

## How to Use the DateDiff () Function in Report Custom Columns?

In this tutorial, we’ll learn how to calculate the **difference between two dates** using the `DateDiff` function in a report grid. This is helpful for calculating aging, due periods, or durations between dates.

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### Accessing the Expression Designer:

* Navigate to the **Reporting** section.
* Open the **Sales Register Detailed Report** or any **"Report".**
* Go to **Setup Column Attributes**.
* Here, you'll see a list of available columns that can be used to build expressions.
* Click on **"Add/Edit Expression Columns"** where you can write your expression using predefined functions.

<figure><img src="/files/QqZlgPb7nJy0O1lsvxB5" alt=""><figcaption></figcaption></figure>

* Before adding the expression to the report, go to **Other Settings**.
* Ensure the **Script Editor** is set to **VBScript**.

<figure><img src="/files/US8rZzar6siLdptkuOMX" alt=""><figcaption></figcaption></figure>

* Click **Save**.
  * *Note: VBScript is the default for new configurations but always verify this setting.*

### Writing Your First Expression

* Every expression must start with the script header: **'#@LSCRIPT**

<figure><img src="/files/K37bBe9AvTCKOiLXaocU" alt=""><figcaption></figcaption></figure>

* Click the (+) Plus icon to create a new expression.
* Fill in the required fields:&#x20;
  * **Expression Name** – A unique name for your expression.
  * **Expression Type** – Choose either **Text** or **Numeric** depending on the expected output.

<figure><img src="/files/9jljzCmx2wf2EXmzBbT9" alt=""><figcaption></figcaption></figure>

### Creating a Simple DateDiff() Expression

* Double-click the new expression name to insert it into the script editor.
* Define the expression using the syntax:
  * **Expression Name** = DATEDIFF("D",CDATE(BILL\_DATE),NOW)

    * `"D"` → Calculates difference in **days**
    * `CDate(BILL_DATE)` → Converts the bill date string to a date
    * `Now` → Represents the current system date

    **Other interval options:**

    * `"M"` – Months
    * `"Y"` – Years
    * `"D"` – Days (most commonly used)

<figure><img src="/files/UPbbGMgp9TI8IZEA5WsI" alt=""><figcaption></figcaption></figure>

* Save the expression once defined.
* Scroll down and **check the box** beside the expression name to enable it.

<figure><img src="/files/MQzcb1J5JYmGsj12kOF8" alt=""><figcaption></figcaption></figure>

* Save and proceed to check the effect.
* **Refresh the report** to view the final result.

<figure><img src="/files/y1Qh5azXu0kzB7O8GIof" alt=""><figcaption></figcaption></figure>

***

### Output:

* If `BILL_DATE = 01/06/2025` and today is `09/06/2025`,\
  the column will show: `8`

This expression is widely used in reports like **aging analysis**, **credit control**, and **follow-up tracking**.


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