Day 7: Power Query Editor – M Language and Advanced Tools in Power BI

On Day 7, we explore M Language (Mashup Language), the advanced editor in Power Query, along with useful tools, views, and parameters that make data transformation more flexible and reusable.

1. M Language (Mashup Language)

M Language is a functional programming language used in Power Query to perform data transformation and automation. It is often called M Code.

Key Features and Usage

• Functional language: Focused on defining “what to do” rather than “how to do it” step by step.

• Programming language: You can write complex scripts to manipulate data.

• Advanced Editor: M language is essentially what you use in the Advanced Editor in Power Query.

Usage:

• Clean and transform data efficiently.

• Perform multiple transformations at once.

• Reuse code across multiple datasets or queries.

Structure of M Code:
M code is a combination of operators and functions. Power BI contains over 950 M functions that cover text, numbers, date, time, and data transformation operations.

Finding all M functions:

1. Go to Blank Query in Power Query.

2. Enter = #shared in the formula bar.

3. This will display a complete list of available functions.

Example M Code:

These examples show how you can assign variables, perform calculations, and return a result dynamically.

2. Views in Power Query

Power Query provides multiple views to monitor, validate, and understand your data:

• Query Settings – Displays all applied steps in a query.

• Column Quality – Shows valid, error, or missing values for each column.

• Column Distribution – Visualizes the distribution of values in a column.

• Column Profiling – Combines quality and distribution with statistics like min, max, and average.

• Go to Column – Quickly navigate to a specific column.

• Advanced Editor – Write or edit M code manually.

• Query Dependencies – Shows relationships between different queries in a visual map.

3. Tools and Help

Power Query offers several help resources for learning and support:

• Guided Learning

• Documentation

• Training Videos

• Support

• About

• Sample Datasets

• Community Forums

These tools help beginners and professionals alike to master M language and Power Query transformations.

4. Parameters

Parameters allow you to dynamically change values in your queries. For example:

• Changing a file path dynamically

• Updating thresholds for filters

• Switching between datasets without editing the entire query

Parameters make your queries flexible, reusable, and adaptable to changing data or requirements.

Power Query Editor combined with M Language, views, and parameters is incredibly powerful. By mastering these, you can automate complex transformations, improve data quality, and save significant time in your data analysis workflow.