𝗧𝗼𝗽 𝟯 𝗙𝗥𝗘𝗘 𝗣𝘆𝘁𝗵𝗼𝗻 𝗖𝗲𝗿𝘁𝗶𝗳𝗶𝗰𝗮𝘁𝗶𝗼𝗻 𝗖𝗼𝘂𝗿𝘀𝗲𝘀 𝗜𝗻 𝟮𝟬𝟮𝟲! 🚀💻

These FREE certification courses can help you build strong programming skills and stand out from the crowd 👇

✅ Free Learning Resources
✅ Certificate Opportunities
✅ Beginner Friendly
✅ Boost Your Resume & Tech Skills

🌟 Perfect for students, freshers, aspiring developers, data analysts, and tech enthusiasts.

🔗 𝗘𝗻𝗿𝗼𝗹𝗹 𝗙𝗼𝗿 𝗙𝗥𝗘𝗘👇:

https://pdlink.in/43DnP6S

📌 Start learning today and level up your career with Python!

🧠 SQL Interview Question (Moderate–Tricky & Duplicate Transaction Detection)
📌

transactions(transaction_id, user_id, transaction_date, amount)

❓ Ques :

👉 Find users who made multiple transactions with the same amount consecutively.

🧩 How Interviewers Expect You to Think

• Sort transactions chronologically for each user
• Compare the current transaction amount with the previous one
• Use a window function to detect consecutive duplicates

💡 SQL Solution

SELECT
user_id,
transaction_date,
amount
FROM (
SELECT
user_id,
transaction_date,
amount,
LAG(amount) OVER (
PARTITION BY user_id
ORDER BY transaction_date
) AS prev_amount
FROM transactions
) t
WHERE amount = prev_amount;

🔥 Why This Question Is Powerful

• Tests understanding of LAG() for row comparison
• Evaluates ability to identify patterns in sequential data
• Reflects real-world use cases like detecting suspicious or duplicate transactions

❤️ React if you want more tricky real interview-level SQL questions 🚀