Coding Interview Preparation
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Coding interview preparation for software engineers Interview questions, DSA, clean solutions. Join 👉 https://rebrand.ly/bigdatachannels Buy ads: https://telega.io/c/coding_interview_preparation DMCA: @disclosure_bds Contact: @mldatascientist
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Top 20 SQL INTERVIEW QUESTIONS
1️⃣ Explain Order of Execution of SQL query
2️⃣ Provide a use case for each of the functions Rank, Dense_Rank & Row_Number ( 💡 majority struggle )
3️⃣ Write a query to find the cumulative sum/Running Total
4️⃣ Find the Most selling product by sales/ highest Salary of employees
5️⃣ Write a query to find the 2nd/nth highest Salary of employees
6️⃣ Difference between union vs union all
7️⃣ Identify if there any duplicates in a table
8️⃣ Scenario based Joins question, understanding of Inner, Left and Outer Joins via simple yet tricky question
9️⃣ LAG, write a query to find all those records where the transaction value is greater then previous transaction value
1️⃣ 0️⃣ Rank vs Dense Rank, query to find the 2nd highest Salary of employee
( Ideal soln should handle ties)
1️⃣ 1️⃣ Write a query to find the Running Difference (Ideal sol'n using windows function)
1️⃣ 2️⃣ Write a query to display year on year/month on month growth
1️⃣ 3️⃣ Write a query to find rolling average of daily sign-ups
1️⃣ 4️⃣ Write a query to find the running difference using self join (helps in understanding the logical approach, ideally this question is solved via windows function)
1️⃣ 5️⃣ Write a query to find the cumulative sum using self join
(you can use windows function to solve this question)
1️⃣6️⃣ Differentiate between a clustered index and a non-clustered index?
1️⃣7️⃣ What is a Candidate key?
1️⃣8️⃣What is difference between Primary key and Unique key?
1️⃣9️⃣What's the difference between RANK & DENSE_RANK in SQL?
2️⃣0️⃣ Whats the difference between LAG & LEAD in SQL?
Elements_of_Programming_Interviews_The_Insiders’_Guide_PDFDrive_.pdf6.27 MB
Series: Smarter Coding Interview Prep
Your Daily Interview Practice Routine (3/3)
Consistency beats cramming. Here’s a proven 90-minute routine:
20 Minutes – Theory & Concept Review
📚 Pick 1 topic.
🔍 Review concept, complexity, edge cases.
🎥 Use a short video or summary.
📝 Keep a “concept notebook.”
50 Minutes – Problem Solving
🕵️♂️ 10 min: Plan.
💻 25 min: Implement.
⚙️ 10 min: Optimize.
✅ 5 min: Test cases.
🧠 Simulate interview thinking process.
20 Minutes – Post-Mortem Review
🔍 Compare with optimal solution.
🐢 Note slow points.
📌 Tag new patterns.
Bonus: Weekly Layer
🎯 1 mock interview.
🔄 Redo problems you got wrong.
Practice this daily and you’ll focus your learning, remember concepts longer, and spot patterns faster in real interviews.
✅ This series is now complete!
That wraps up our Smarter Coding Interview Prep series. A new topic and series are coming soon.
💬 Drop your ideas in the comments, your suggestion might be next!
