Book Image

Learn Power Query

By : Linda Foulkes, Warren Sparrow
Book Image

Learn Power Query

By: Linda Foulkes, Warren Sparrow

Overview of this book

<p>Power Query is a data connection technology that allows you to connect, combine, and refine data from multiple sources to meet your business analysis requirements. With this Power Query book, you’ll be empowered to work with a variety of data sources to create interactive reports and dashboards using Excel and Power BI. </p><p>You’ll start by learning how to access Power Query across different versions of Excel and install the Power BI engine. After you've explored Power Pivot, you’ll see why Excel users find it challenging to clean data in Power Pivot and learn how Power Query can help to tackle the problem. The book will show you how to transform data using the Query Editor and write functions in Power Query. A dedicated section will focus on functions such as IF, Index, and Modulo, and creating parameters to alter query paths in a table. You’ll also work with dashboards, get to grips with multi-dimensional reporting, and create automated reports. As you advance, you'll cover the M formula language in Power Query, delve into the basic M syntax, and write the M query language with the help of examples such as loading all library functions offline in Excel and Power BI. Finally, the book will demonstrate the difference between M and DAX and show how results are produced in M. </p><p>By the end of this book, you’ll be ready to create impressive dashboards and multi-dimensional reports in Power Query and turn data into valuable insights.</p>
Table of Contents (17 chapters)
Free Chapter
1
Section 1: Overview of Power Pivot and Power Query
6
Section 2: Power Query Data Transformations
11
Section 3: Learning M

Creating a parameter table for queries

When we design a query for something specific, for example, a monthly sales query, we would generally create it for that month. The following month, we would want to use the same query but have a different source document. Naturally, we would not want to redo the entire query but just change the query for that specific month. So, in this way, we can make the necessary additions to the query to make our lives easier and create a parameter to the query.

I am using the same Excel files from Chapter 4, Connecting to Various Data Sources using Get & Transform. The following is a CSV file that I have opened and I have connected it to a query:

Figure 6.9 Imported CSV file in the query

Figure 6.9 – Imported CSV file in the query

When you edit the query, you will see that it is a simple one with mostly the default steps. The only thing I have added is that I have changed the Sales column to the currency type.

If you click on the gear icon on the right...