4-Week Study Plan for DE Interviews
You already know this stuff. You have built pipelines, debugged Airflow DAGs at 2 AM, and argued about star schemas in design reviews. But it has been a while since you interviewed, and the gap between doing the work and explaining the work in a high-pressure setting is real.
This plan is not about learning from scratch. It is about sharpening what you already know, filling the gaps you have been ignoring, and building the muscle memory to perform under interview conditions.
Who this is for: Working data engineers with 1+ years of experience who have an interview coming up in roughly a month.
Time commitment: 2-3 hours per day, 5 days per week. Weekends are for rest or light review.
The 4-Week Overview
| Week | Focus Area | Primary Goal |
|---|---|---|
| 1 | SQL Deep Dive | Solve hard SQL problems fluently under time pressure |
| 2 | System Design | Build a repeatable framework for designing data systems |
| 3 | Python Patterns + Data Modeling | Cover coding rounds and modeling discussions |
| 4 | Mock Interviews + Behavioral + Review | Simulate real conditions and patch weak spots |
Week 1: SQL Deep Dive
SQL rounds are the most common filter in DE interviews. You know SQL, but can you solve a medium-hard window function problem in 20 minutes while someone watches? That is a different skill.
Day 1 — Window Functions Refresher
- Review ROW_NUMBER, RANK, DENSE_RANK, LEAD, LAG, and running aggregates
- Study the SQL course — focus on the window functions section
- Solve 5 window function problems on the coding problems platform
- Time yourself: aim for under 15 minutes per problem by the end of the week
Day 2 — CTEs and Recursive Queries
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