Read the business rule
Identify what the result should represent before writing SQL.
PRACTICE LAB
Solve. Learn. Build.
Sharpen your data engineering skills with real-world problems. Practice SQL, Python, and PySpark with hands-on datasets.
↗Real-worldscenarios
◉Curateddatasets
✦Step-by-stephints
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▤10+Problems
▥3Difficulty Levels
▦10+Topics
▣1Practice Workspace
Practice
real data ↘
real data ↘
DEX DataEngineerX / Practice Lab
01-- Find customers with 3+ orders
02SELECT customer_id,
03 COUNT(*) AS total_orders
04FROM orders
05GROUP BY customer_id
06HAVING COUNT(*) >= 3;
07ORDER BY total_orders DESC;
✓
Query executed successfully!12 rows returned · 28 ms
● Ready
customer_idtotal_orders
1015
2054
3094
4123
Learn by doing
Real problems. Real progress.
Real problems. Real progress.
THE PRACTICE BANK
Pick a problem.
Make it yours.
Choose a language, narrow the difficulty, search by topic, and solve challenges that test real engineering reasoning—not memorized syntax.
SQL / INTERVIEW PRACTICE
SQL Problems
5 problems
HOW TO USE THE BANK
Think first.
Code second.
Inspect the data
Use the supplied rows to reason about edge cases and grain.
Build in layers
Use hints only when needed, then verify the final output.
READY?