So here's the thing - I started this repository with a clear mission: identify 25 essential SQL patterns that would cover 80% of what any data scientist needs for querying, manipulation, and analysis. You know, create the ultimate reference guide.
But life had other plans.
What actually happened? I got hooked on solving real problems on StrataScratch. Instead of neatly categorizing patterns, I found myself deep in the trenches, solving question after question. And honestly? I learned way more doing that than I would have just writing about theoretical patterns.
This repository is now a collection of 30+ SQL solutions I've worked through on StrataScratch. These aren't just textbook examples - they're real interview questions from companies like Facebook, Apple, Amazon, and more.
All solutions are in the sql-solutions/ folder, with each file named after the StrataScratch question ID. Every solution includes:
- A link to the original problem on StrataScratch
- My SQL solution with comments explaining the approach
- Real-world context from actual company interviews
You'll still find a couple of pattern folders (pattern-1, pattern-2) from my initial attempt. They're staying here as a reminder of where this started - and maybe one day I'll circle back and properly categorise everything I've learned.
The original belief still holds: there ARE core SQL patterns you need to know. But I've discovered that the best way to learn them isn't by studying them in isolation - it's by solving real problems and recognizing the patterns as they emerge naturally.
So if you're here to learn SQL, don't just read the code. Go to StrataScratch, try the problems yourself, then come back and see how I approached them. That's where the real learning happens.
Started as a quest for 25 patterns. Ended up with 30+ real solutions. Still learning.