Tablas calculadas

How to generate calculated tables in Power BI?

Let's explore the fascinating world of calculated tables in Power BI, an indispensable tool for data analysts. These allow you to create custom dimensions from existing ones in the model, such as a calendar table. Learning how to handle these functionalities expands our analytical capabilities and optimizes the way we filter and represent information.

How to create a calendar table in Power BI?

Creating a calendar table is crucial for working with time-related data. Even though your dataset may include a date table, learning how to build it from scratch is essential for deeper understanding and customization.

1. Remove the existing calendar table: If your dataset already contains a calendar table, delete it (right click, delete) to avoid duplicates.

2. View Data and Create New Table: Go to the "Data" view and select "Table Tools" to create a new table. This will be our calendar table. Use the CALENDAR function to define a specific date range:

   DimDates = CALENDAR( DATE(2015, 1, 1), DATE(2017, 12, 31))

3. Date Format: Sets the date column to the appropriate format, i.e. date only (no time).

How to set calculated columns?

Once we have our date table, it is time to add calculated columns that allow us to perform more detailed analysis.

1. Add descriptive columns: Start by adding columns such as year, month and week. This is accomplished using the DAX functions YEAR, FORMAT, and WEEKNUM:

   Year = YEAR(DimDate[Date])
   Month = FORMAT(DimDate[Date], "mmmm")
   Week = WEEKNUM(DimDate[Date])

2. Create a key field (DayKey): This is essential to connect our date table with other fact tables. It uses concatenated year, month and day values:

   DayKey = VALUE(FORMAT(DimDates[Date], "YYYYYYMMDDD")).

How do we order the visualizations correctly?

To ensure that our visualizations show the months in a sequential order, we must sort the columns using a numerical reference.

1. Sort by month number: Select the 'Month' column and use "Column Tools" to sort by 'MonthNumber'. This will ensure that the months are shown in the correct order in both charts and reports.

When to use calculated tables?

Calculated tables are indispensable for creating additional dimensions that enhance the analysis of your data, such as calendar tables that enable the use of Time Intelligence in Power BI. This approach is vital to:

• Avoiding temporal gaps: Ensures that all periods are represented, which is critical for comparative analysis.

• Empowering data analysis: By adding descriptive columns, you can perform more detailed and specific slices that help gain valuable insights.

Finally, as a challenge to further this knowledge, try adding a column that identifies the day of the week, showing results from "Monday" to "Sunday". This practice will further enrich your analytical capabilities in Power BI. Keep exploring and developing your skills to reach new heights in data analysis.