Guides, cheat sheets and what's new in data.
37 practical, copy-ready resources on SQL, Python, Snowflake, dbt, Power BI, databases and Swift. Free to read, save and print.
Best AI models, October 2026
A dozen frontier releases in six weeks. Here is how they compare on quality and cost, and which one to pick for analytics, coding and everyday work.
Gemini 4 Argon, explained
Google's most capable model is now open to developers, businesses and paid Gemini users. Where it leads, where it trails, and what the introductory price means.
Databricks: October 2026 update
Rolling averages in metric views, an AI coding assistant in your terminal and charts pulled straight out of PDFs. The October changes worth knowing, with examples.
GPT-6.1 Sol and DevDay 2026
Near-flagship quality at a fifth of the price, always-on personal agents, and a flagship upgrade that was cancelled. The DevDay 2026 announcements that matter.
What's new in Python 3.15
Released on 9 October 2026, with lazy imports, UTF-8 by default, frozendict and a built-in sampling profiler. Here is what matters for data work.
Polars 2.0: what's new
Released on 6 October 2026: streaming is now the default, big queries can spill to disk, and row order is no longer guaranteed unless you ask. Here is what changes.
dbt v2: what changed
dbt v2 replaces the Python engine with a single fast Rust binary, catches mistakes before they reach your warehouse, and is stricter about your YAML. Here is how to move.
Upgrading to pandas 3.0
The biggest pandas release in years changes how strings, copies and dates work. Here is what breaks, how to fix it, and the new features worth using.
DuckDB 2.0: what's coming
The laptop database every analyst loves is getting a server mode, a VARIANT type, triggers and big speed-ups, and it now ships inside dbt. Here is what is changing.
Power BI: September 2026 update
AI agents that edit models, faster distinct counts in DAX, full-text search, Export to Excel up to 500,000 rows and PBIP by default. The highlights for report builders.
PostgreSQL 19: what's coming
IGNORE NULLS for window functions, COPY straight to JSON, get-or-create inserts and time-aware updates. Here is what PostgreSQL 19 brings for data work.
Apache Iceberg v3, explained
Iceberg has become the open table format behind modern data platforms. Version 3 makes updates faster, tracks every row and handles JSON natively. Here is what it means for you.
What's new in Swift 6.4
Released on 15 September 2026, with simpler syntax, async work in defer, cancellation shields, Subprocess 1.0 and Swift Build as the default. Here is what changed.
Fivetran + dbt Labs, explained
Two of the most important companies in analytics engineering are now one. Here is what was announced, what stays open source, and what it means for your data stack.
What does an analytics engineer do?
The role that sits between raw data and business decisions, explained in plain English.
The data stack in 2026
Fewer tools, more open formats and AI built into the platform. What has changed, and what it means for data teams.
SQL window functions, explained
The single most useful SQL skill after joins. Rankings, running totals and period-over-period comparisons, without self-joins.
SQL joins, explained visually
Every join type in one place, and the one mistake that quietly doubles your revenue figures.
Star schema data modelling
The data model behind fast, trustworthy dashboards. Facts, dimensions and the one decision that matters most: grain.
Your first dbt project, step by step
How analytics engineers turn SQL scripts into tested, documented, version-controlled pipelines.
Getting started with Snowflake
The concepts that make Snowflake different, and the SQL you need on day one.
SQL cheat sheet
Every query pattern you use day to day, on one printable page.
pandas for Excel users
Everything you already do in Excel, translated into Python, and why it scales better.
What's new in Python 3.14
The October 2025 release brought some of the biggest changes to Python in years. Here is what matters for data work.
Python and pandas cheat sheet
The pandas commands analysts use every day, on one printable page.
Data quality tests every pipeline needs
Six checks that catch most data problems before your stakeholders do.
DAX CALCULATE, explained
The most important function in Power BI, explained through the questions it answers.
Snowflake SQL cheat sheet
Snowflake-specific commands and syntax, on one printable page.
Choosing the right database
A clear way to decide, based on what your data is for rather than what is fashionable.
Automate your weekly report
A complete, working pattern for turning a manual weekly report into one that builds itself.
DAX cheat sheet
The DAX patterns behind almost every Power BI report, on one printable page.
Modern Python setup with uv
One fast tool that replaces pip, virtualenv and pyenv for most projects.
JSON in Swift with Codable
The clean, modern way to bring API data into an iPhone app, with no third-party libraries.
What's new in Swift 6.2
Released in September 2025, Swift 6.2 made strict concurrency far easier to live with. Here is what changed.
Swift cheat sheet
Modern Swift syntax at a glance, on one printable page.
From spreadsheets to dashboards
When spreadsheets start costing you time, and what a sensible next step looks like.
Git cheat sheet
The Git commands data teams actually use, on one printable page.
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