Power Query is a data transformation and ETL (Extract, Transform, Load) tool developed by Microsoft.

It's used in applications like Power BI, Excel, and SQL Server to connect to various data sources, perform data cleansing and transformation, and then load the transformed data into a data model or a worksheet.

Here's more about Power Query:

Data Extraction

Power Query allows you to connect to a wide range of data sources, including databases, files (such as Excel, CSV, JSON, XML), web services, and online sources (like SharePoint lists and online databases).

Data Transformation

Power Query provides a user-friendly interface for performing data transformation tasks, such as filtering, sorting, merging, grouping, pivoting, splitting columns, and more.

These transformations help clean and shape your data for analysis.

Data Combining

Power Query can combine data from multiple sources into a single dataset.

You can merge tables, append data, and join data from different sources.

Data Cleaning

Power Query helps you clean data by removing duplicates, handling null values, and performing data quality checks.

Data Enrichment

Power Query can enrich your data by fetching additional information from web services or external data sources.

User-Friendly Interface

Power Query provides a visual interface where you can define your data transformation steps using a series of user-friendly dialogs and options.

Formula Language (M)

Behind the scenes, Power Query uses a language called "M" to define data transformation steps.

This language is functional and expressive, allowing you to create complex data transformation sequences.

Data Loading

After performing transformations in Power Query, you can load the cleaned and transformed data into a data model (in Power BI) or into an Excel worksheet.

Query Folding

Power Query optimizes data loading by utilizing query folding whenever possible.

This means that it tries to push data transformations back to the data source for efficiency.

Reusability

Power Query lets you create reusable queries and functions, which can be applied to different datasets.

This saves time and promotes consistency.

Data Refresh

Power Query queries can be set to refresh data on a schedule, ensuring that your analysis stays up-to-date.

Power BI Integration

In Power BI, Power Query is used to connect to data sources, transform data, and create queries that feed into your data model.

Power Query is a versatile tool that simplifies the process of data preparation and transformation, making it easier to work with data from different sources for analysis and reporting.

Want to learn more? Check out my "What Is A...." blog series on common Power BI functionality:

What Is A Measure?

What Is A Slicer?

What Is A Paginated Report?

What Is A Date Hierarchy?

What Is A Gateway?