Recursive CTE Practice Sheet – From Fundamentals to Interview-Grade Problems

Recursive CTEs are one of the most powerful — and most misunderstood — concepts in SQL.

This practice sheet is designed to help you truly understand how recursion works, not just write queries that “somehow run”.

The sheet is structured in a progressive manner so learners at all levels can build confidence step by step.

What’s Included

✅Part A: Recursive CTE Fundamentals (15 Problems)

You’ll start with foundation-building problems that focus purely on recursive thinking:

• Mathematical series (Fibonacci, factorials, primes, Catalan numbers)
• String and pattern generation
• Date and time recursion (working days, Sundays, month boundaries)
• Advanced combinations to strengthen termination and iteration logic

Each problem includes a clear expected output, a clean SQL solution, and a step-by-step explanation of how the recursion evolves at every iteration.

✅Part B: Real-World & Interview Scenarios

Once the fundamentals are clear, you’ll move to applied use cases:

• Graph traversal scenarios (paths, levels, cycle prevention)
• Hierarchical datasets (employee hierarchies, reporting chains)
• 5+ SQL interview-grade problems with in-depth execution flow explanations

Here, the focus is not just the final answer, but how the recursive CTE grows row by row — exactly the way interviewers expect you to explain it.

Who this is for

• Beginners who want a strong conceptual foundation
• Intermediate learners struggling to “think recursively”
• Advanced SQL users preparing for interviews or real business problems

Recommended Roadmap

This practice sheet is designed to be followed in sequence for maximum clarity and confidence.

Step 1: Start with Part A (Foundations)

Begin with the 15 fundamental problems to understand:

• How anchor members start recursion
• How recursive members expand results
• How and when recursion terminates

Do not rush this section. The goal is to mentally trace each iteration, not just reach the final output.

Step 2: Move to Part B – Section A (Applied Scenarios)

Once you’re comfortable with the basics, practice:

• graph traversal logic
• hierarchical relationships
• path building and depth tracking

This step bridges the gap between abstract recursion and real-world datasets.

Step 3: Finish with Part B – Section B (Interview Problems)

Use the interview problems as your final checkpoint:

• Attempt the problem on your own first
• Then study the step-by-step execution flow
• Focus on explaining why each iteration exists

Following this roadmap helps ensure you build both technical correctness and confidence in your explanations.

How You’ll Practice

This is a hands-on, thinking-first practice sheet.

• Attempt each problem before looking at the solution
• Manually trace the recursion for the first few iterations
• Compare your intermediate result sets with the explained execution flow
• Re-run the query and observe how each iteration adds new rows
• Revisit difficult problems after a few days to reinforce intuition

You’re encouraged to:

• modify limits and conditions
• add or remove termination logic
• experiment with depth and levels

This approach trains you not just to use recursive CTEs, but to reason through them confidently — a skill that directly translates to interviews and real-world SQL work.

If recursive CTEs have ever felt confusing or intimidating, this practice sheet will help you break that barrier with clarity and confidence.