> For the complete documentation index, see [llms.txt](https://kb.logicerp.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://kb.logicerp.com/logic-erp-learning-hub-tutorials-and-best-practices/defining-custom-columns-in-reports-and-grids-with-expressions/week-function.md).
# Week() Function
**YouTube:** [How to Use the Week() Function in Report Custom Columns?](https://www.youtube.com/watch?v=f8ZDsjjI-h4)
## How to Use the Week() Function in Report Custom Columns?
In this tutorial, we'll learn how to design expressions using the `Weekday` function to retrieve the **day number of the week** (e.g., 1 = Sunday, 2 = Monday) from a date field like *Bill Date* in the reporting grid.
***
### 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.
* Before adding the expression to the report, go to **Other Settings**.
* Ensure the **Script Editor** is set to **VBScript**.
* 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**
* Click the (+) Plus icon to create a new expression.
* Fill in the required fields:
* **Expression Name** – A unique name for your expression.
* **Expression Type** – Choose either **Text** or **Numeric** depending on the expected output.
***
### Creating a Simple Week() Expression
* Double-click your newly created expression to insert it into the script editor.
* Define the expression using the syntax:
* Expression Name = WEEK(CDATE(BILL\_DATE))
* `Weekday(...)` returns the day number of the week (e.g., 1 for Sunday).
* `CDate(BILL_DATE)` converts the field to a proper date format.
* Save the expression once defined.
* Scroll down and **check the box** beside the expression name to enable it.
* Save and proceed to check the effect.
* **Refresh the report** to view the final result.
***
### Result:
The new column will display the **weekday number** on which the bill was generated.\
For example: if the *Bill Date* is a **Monday**, the result will be `2`.
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