Creating a Calendar Table in Excel Power Query and its Benefits

Introduction

Excel Power Query is a powerful tool that allows the transformation and manipulation of data for more effective analysis and reporting. One valuable technique to transform data is the creation of a calendar table, which typically helps to manage and visualize time-related data. In this article, we will go through the process of creating a calendar table using Power Query and explore the many benefits it offers.

Creating a Calendar Table in Power Query

To create a calendar table, we are going to launch the Power Query editor.

In the Get & Transform group of the Data tab, click on the Get Data dropdown and select Launch Power Query Editor.

In the Power Query editor, we need to create an artificial table we can modify. To do that, in the Home tab, click on Enter Data.

• In the Create table window, just type in any value.
  
• In the Formula Bar, execute this M Code to generate a list of dates starting from January 1, 2010.

  = List.Dates(#date(2010,1,1),365,#duration(1,0,0,0))

• Click Enter to commit.

• In the screenshot below, we have the list of dates.
  
  We need to convert it to a Table to create other components of the Calendar Date, such as extraction of Year, Month, etc. 
• To do that, at the top left corner of the screen, click To Table.
  
• In the To Table dialogue box, click OK. The date values are now in a table with the column renamed as Date, the data type specified as Date data type, and the Query renamed as DimDate, as seen in the screenshot above.
• To extract the Year and Month name from the Date column, click on the Add Column tab, click on the Date dropdown, and select Year and Year. 
  
• Repeat the above step and select Month and Name of Month
• In the screenshot below, we have the Date, Year, and Month columns.
  

Then, we can load it into the Power Pivot data model and use it to perform time-based calculations.

Benefits of a Calendar Table in Excel Power Query

• Ease of Data Analysis: With a calendar table, time-based data can easily be analyzed, such as Total Sales by Month or Year. You can join this table with other data tables to gain insights, create reports, and make informed decisions.
• Consistency: The calendar table ensures data consistency and accuracy. It prevents data gaps and makes it simple to handle missing or irregular data points.
• Automation: The calendar table can be set to auto-update, saving you the trouble of manually adjusting it each time new data is added. This automation is particularly beneficial for long-term projects or ongoing data tracking.
• Time Intelligence Functions: Excel's Power Pivot, which often complements Power Query, offers time intelligence functions that become even more powerful when you have a calendar table. Functions like TotalYTD, TotalQTD, and TotalMTD can provide cumulative values based on your calendar's time periods.
• Customization: You can customize your calendar table to suit your needs. Add additional columns or attributes, set fiscal years, or even integrate holiday schedules for more advanced calculations.

See you in the next article.