Power Query M, a language commonly referred to as “M,” is a powerful data transformation and data preparation language designed specifically for Microsoft’s Power Query, an ETL (Extract, Transform, Load) tool integrated into the Power BI, Excel, and other Microsoft products.
M was developed with the purpose of allowing users to clean, reshape, and combine data from various sources, facilitating the process of transforming raw data into the desired shape. By using the power of M, users can create custom functions, conditional columns, and advanced data transformations that go beyond what traditional spreadsheet applications can do.
Updated Articles
With 1100+ articles it’s an enormous task to update all documentation. Therefore the website skeleton consists of Microsoft documentation. To see the changes made by me check out the updates articles section.
Functions
The Power Query M language has different types of functions. Learn about each by using the sidebar or by choosing a category below:
Enumerations
The M language provides a range of enumerations. These simplify the process of selecting options within a function. For example, you have the option to provide the Date.StartOfWeek function with the first day of the week by writing Day.Monday. Yet to be more concise you could enter the short-hand value 1. The Enumeration Overview delves into all enumerations and their short-hand alternatives.
Constants
Constant values are values that do not change. The M language supports several and they provide an easy way to input values that are immutable. More on these in the Constants Overview.
Value Types
A type value is a value that classifies other values. The M Language provides an extensive list of type values to classify values into data types. Explore all in the Types Overview.
Dynamic Values
A dynamic value is a value that takes into account your personal settings, resulting in potentially different values for each user. The M Language offers a limited selection of dynamic values to cater to varying user environments. Find all in the Dynamic Values Overview.
About this Reference
This Power Query reference contains comprehensive information on the M language. The Guide is updated regularly to reflect the latest changes in Microsoft products. Each M function is presented with a syntax, supporting articles and often with examples.
While this Power Query Guide is a BI Gorilla project created and maintained by Rick de Groot, it also incorporates official Microsoft documentation to provide you with the most accurate and up-to-date information.

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