Data Analytics & Business Intelligence

Expected value is often presented as a betting concept, but the underlying idea should feel familiar...

Build a practical competitor pricing and promotion data pipeline for food delivery, including scraping, normalization, alerts, and failure checks.

Data has become one of the most valuable assets for modern enterprises, powering everything from...

Picture a small shop owner in Kathmandu, closing up for the night. She's staring at the register...

Financial markets produce enormous amounts of data—but converting raw order-book updates into...

Most small businesses do not have a data problem. They have a decision problem. The data is already...

Two years ago, I spent six weeks migrating a 400TB churn-prediction dataset from Delta Lake 2.4 to...

AI-written SQL usually runs, and running is not the same as right. Five checks that catch the wrong number: join fan-out, NULL in the filter, WHERE vs HAVING, t

The MoM growth formula, LAG() in everyday words, and the trap where one skipped month makes SQL report a fake 30.6% drop. Every query run on a real table.

groupby, agg, size vs count, transform, and dropna, worked on one 14-row table. Two rows vanish from the default result, and one line brings them back.

Drop a column into a pivot's Values and Excel picks Sum for anything numeric, including ID codes. The test that catches it, and the ten-second fix.

How to add a slicer and connect it to every pivot with Report Connections: the moment a spreadsheet becomes a dashboard.

Data Pipelines: The Foundation of Data Engineering One of the first concepts I believe...

When merging CSVs in the browser, handling mismatched columns and quoted cells changes everything....

Two merges, four open PRs, and ninety days of building in public — what actually worked for upstream contributions as a senior data engineer.

A current course average is not enough to answer a planning question. If 35% of the course is still...

Establish ownership, versioning, and validation for features. Governance patterns that increase reuse and reduce incidents.

In the third quarter of 2021, Zillow's home-pricing algorithm was still running exactly as designed....

Storing RAG conversation history server-side is deceptively complex—naive approaches silently corrupt...

As enterprise data architectures evolve toward unified cloud data platforms, moving away from legacy...

Skip the docs. Here’s the Polars syntax you’ll actually use every day, distilled from production pipelines and our O’Reilly book.

A sync ledger fails silently. Ours said 763 assets. When we stopped trusting it and counted by hand —...

A verifier should add evidence, not rewrite history I spent the last few weeks closing a...

Nearly half of DE job postings may never be filled. Candidates spend 20 hours on take-homes for roles that aren't real. Here is what is actually happening.

Measure customer sentiment from G2: scrape B2B software reviews with ratings, roles, and company size as JSON via Python or MCP.

When I built Confrontational Meditation® in late 2025, I wasn't trying to create another trading...

Four numbers from a nine-day-old codebase, measured this week across two providers: Summing every...

Build a Personal Finance Dashboard with Python tags: python, finance, dashboard,...

Introduction When managing large-scale data migrations, ETL pipelines, or multi-database...

description: "The key didn't match any rows in the table" comes from LOOKUPVALUE finding zero...

On August 13, Flock Safety CEO Garrett Langley announced that the company is cutting its default...

Data privacy is one of those topics everyone has an opinion on, but few people fully understand, and...

The Quest Begins (The "Why") I was refactoring a data‑processing script that read a CSV of...

Fastmail offers EU data region — daily AI analysis from 🇺🇸 United States.

I built a Python package to diff large data files — here's why existing tools weren't enough Every...

If you manage projects, track team hours, prepare timesheets, or calculate billable hours, you have...

When integrating WhatsApp verification services into your application, the most common pitfall isn't...

"Smile because it happened" — Dr. Seuss The Setup Earlier this year, I took on a...

I've spent more than a decade building data pipelines, and the part nobody warns you about isn't the...

Every analysis needs cutoffs — minimum reviews, minimum votes, 'active user' definitions. Beginner guide to choosing thresholds from the data instead of guessin

A file too big to open in Excel? Beginner guide to working with large datasets: what counts as large, why a database beats a spreadsheet, indexing, sampling, an

Step-by-step beginner guide: set up your first SQL database with SQLite and DB Browser, import a CSV file, and run your first query. Two desktop tools, no serve

Nine analyst roles compared on the work, the skills, the pay in four countries, the difficulty of entry, and where each one leads.

Build a production-grade CDC pipeline with Debezium 2.6, Kafka, and dbt 1.8 — idempotent MERGEs, backfill strategy, and monitoring that actually pages you.

Market mapping with Apple Maps data: pull business listings, multi-source ratings, and phone numbers as JSON via Python or MCP.

Every company dataset I have worked with stores history as scalar columns: founded_year ...

PostgreSQL Error 22012: Division by Zero — Causes, Fixes & Prevention PostgreSQL error...

ORA-02049: Timeout – Distributed Transaction Waiting for Lock ORA-02049 occurs in Oracle...