The Library · Insights
Deep dives across data, automation & AI
109 in-depth articles — from Excel foundations to production machine learning. Filter by topic or difficulty to find exactly what you need.
Power QueryPractitioner
Building a Dynamic Date Dimension Table in Power Query Using Pure M Code
Stop maintaining static date CSVs that break at year-end. This deep-dive lesson shows you how to build a fully dynamic, self-updating date dimension table in Power Query M code — complete with fiscal year logic, ISO week numbers, and relative date flags that update automatically on every refresh.
22 min read
Power QueryFoundation
Conditional Logic and Dynamic Column Selection in Power Query M: Mastering if-then-else, each, and Predicate Functions
Most Power Query users hardcode column names and write static transformations — then their queries break the moment the source data changes. This lesson teaches you to use M's if-then-else, the each keyword, and predicate functions to write queries that think dynamically, adapt to schema changes, and classify rows with multi-condition logic.
14 min read
Power QueryFoundation
Understanding Query Dependencies and Evaluation Order in Power Query: How the M Engine Executes Your Steps
Power Query doesn't run your steps in the order you wrote them — it uses a dependency-driven evaluation model that surprises almost every new user. Learn how the M engine actually decides what to compute, when, and why, so you can write faster and more reliable queries.
15 min read
Power QueryExpert
Implementing Custom Table.Buffer and In-Memory Caching Strategies in M to Eliminate Redundant Query Recalculations
Power Query's lazy evaluation engine can silently recalculate the same query steps dozens of times — and most developers never know it's happening. This expert-level lesson teaches you how to diagnose redundant evaluations with Query Diagnostics, apply Table.Buffer with surgical precision, and architect multi-query caching systems that cut refresh times by 50–80%.
25 min read
Power QueryExpert
Implementing Row-Level Security Data Preparation in Power Query: Filtering and Shaping Data for Role-Based Access Models
Row-Level Security enforcement lives in Power BI, but the data structures that make it work — or break it — are built in Power Query. This expert-level lesson teaches you how to design user mapping tables, security bridge tables, and hierarchical access models in M that are robust, performant, and production-ready.
27 min read
Power QueryPractitioner
Building Multi-Stage ETL Pipelines in Power Query M: Orchestrating Dependent Transformations with Modular Query Chains
Most Power Query pipelines collapse under their own complexity because they mix extraction, transformation, and business logic in the same queries. This lesson teaches you to architect multi-stage ETL pipelines where each query has a single job, dependencies are explicit, and the whole chain is debuggable and maintainable — the way serious production pipelines are built.
20 min read
Power QueryPractitioner
Managing Many-to-Many Relationships in Power Query: Deduplication, Bridge Tables, and Safe Merge Strategies
Many-to-many joins are the most common source of silent data corruption in Power Query — and they produce no error messages. Learn how to detect M:N relationships before they inflate your totals, and master three strategies to handle them correctly: deduplication, bridge tables, and defensive merge patterns.
21 min read
Power QueryFoundation
Text Manipulation and String Functions in Power Query M: Parsing, Splitting, and Transforming Text Data
Raw data is almost always messy — names in all-caps, addresses crammed into one column, phone numbers formatted six different ways. This lesson teaches you to parse, split, extract, and rebuild text data using Power Query's M language functions, with real scenarios and hands-on practice.
15 min read
Power QueryFoundation
Reshaping Data with Transpose, Fill Down, and Fill Up in Power Query
Messy data rarely arrives in the shape you need it. This lesson teaches you how to flip, fill, and restructure tables in Power Query using Transpose, Fill Down, and Fill Up — the three tools that turn awkward exports into clean, analysis-ready datasets.
17 min read
Power QueryExpert
Implementing Row-Level Security and Dynamic Data Filtering Pipelines in Power Query M Using Parameter-Driven Permission Tables
Learn how to build a production-grade, parameter-driven row-level security system entirely in Power Query M. This expert lesson covers permission table design, dynamic predicate construction, union vs. intersection filter semantics, query folding implications, and full testability patterns — everything you need to implement real security filtering in your data pipelines.
28 min read
Power QueryExpert
Building Custom Connectors in Power Query: Extending Data Source Support with the M SDK
Learn to build production-grade Power Query custom connectors from scratch using the M SDK. This deep-dive lesson covers OAuth 2.0 authentication, navigation tables, pagination, schema enforcement, and distribution — everything a real connector needs.
28 min read
Power QueryPractitioner
Streaming and Pagination Patterns in M: Handling Large APIs and Multi-Page Data Sources with Custom Iterators
Most Power Query tutorials stop at fetching one page of API data. This lesson goes all the way — teaching you how to build robust, production-ready pagination handlers in M that work across offset-based, cursor-based, and link-header APIs using List.Generate and custom iterators. You'll leave with reusable code and a mental model that makes any paginated API manageable.
21 min read