Practical writing on data systems

Clear, experience-driven posts about SQL, data engineering, and Python.

This blog focuses on:

  • Writing correct and efficient SQL
  • Designing data models that scale
  • Automating data workflows with Python
  • Working across SQL Server, PostgreSQL, and Snowflake

Latest posts ↓

A Lesser-Known SQL Function for Financial Data Analysis
Hey there! Recently, I ran into a somewhat forgotten SQL function called SIGN(). While it’s a mathematical function that isn’t commonly associated with financial analysis, it can be a surprisingly powerful tool in the right scenarios.
2024/02/22 · Posts
Automate Excel Reports with Python and SQL
Excel is a powerful tool for creating reports, charts, and analyzing data. However, when reports rely on large datasets stored in a SQL database, manual extraction quickly becomes inefficient and error-prone.
2024/01/03 · Posts
How to Use the STRING_SPLIT() Function in SQL Server
Hello and welcome back to another post! Recently, I was reviewing some stored procedures used to generate reports. These procedures accepted several parameters — some nullable, others allowing multiple values.
2019/09/04 · Posts
How to Use the STRING_AGG() Function in SQL Server
Hello again! How many times have you needed to create a list of values separated by commas? I’ve been in that situation many times, and I’m sure you have too. Before SQL Server 2017, doing this usually meant ugly XML tricks using STUFF, FOR XML PATH, and other hacks. Thankfully, SQL Server 2017 introduced a much better solution.
2019/05/30 · Posts