Power Query is a powerful data transformation tool available in Excel and Power BI. It allows users to connect, clean, and reshape data from various sources without writing complex code. Whether you’re a beginner or an advanced user, Power Query simplifies ETL (Extract, Transform, Load) processes, making data preparation faster and more efficient.

1. Key Features of Power Query

A. Connect to Multiple Data Sources

📌 Supports connections to Excel, databases, web data, SharePoint, APIs, and cloud services.
📌 Helps in consolidating data from different sources into a single table or model.

B. Easy Data Cleaning and Transformation

📌 Provides tools to remove duplicates, filter rows, split columns, merge datasets, and change data types.
📌 Automates data preparation, reducing manual errors.

C. Automate Data Refresh

📌 Saves transformation steps as reusable queries.
📌 Can schedule automatic refresh in Power BI or refresh manually in Excel.

2. How to Connect to Different Data Sources Using Power Query

A. Connecting to Excel Files

  1. Open Excel and go to Data → Get Data → From File → From Workbook.
  2. Select the file and click Import.
  3. Choose the worksheet or table and Load it into Power Query.

B. Connecting to SQL Server

  1. Go to Data → Get Data → From Database → From SQL Server Database.
  2. Enter the server name and database details.
  3. Select tables, apply transformations, and Load into Excel or Power BI.

C. Connecting to Web Data & APIs

  1. Go to Get Data → From Web and enter the URL.
  2. Use authentication if required.
  3. Extract and clean web data with Power Query’s tools.

3. Understanding M Language: The Backbone of Power Query

Power Query uses the M Language to record transformation steps. While the UI provides a no-code experience, knowing M Language helps in customizing queries.

A. Basics of M Language

📌 M code is generated automatically when performing transformations.
📌 It follows a step-by-step functional approach.

Example:

let
    Source = Excel.CurrentWorkbook(){[Name="SalesData"]}[Content],
    FilteredRows = Table.SelectRows(Source, each [Sales] > 1000)
    in
    FilteredRows

B. Editing M Code in Power Query

  1. Click Advanced Editor in Power Query.
  2. Modify the generated M script to create custom transformations.
  3. Save and apply changes to the dataset.

4. Step-by-Step Guide to Power Query’s User Interface

A. Home Tab

📌 Get Data – Connects to different sources.
📌 Close & Load – Saves transformations and loads data.

B. Transform Tab

📌 Tools to split columns, replace values, remove duplicates, pivot data, and merge queries.

C. Add Column Tab

📌 Allows users to create custom columns, conditional columns, and invoke functions.

D. View Tab

📌 Access to Advanced Editor for modifying M Language.

Conclusion

✅ Power Query is a game-changer for data analysts, making data preparation easy, automated, and efficient. By understanding its UI, M Language, and data source connections, you can save hours of manual work and focus on data-driven insights.