🚀 5 Frequently Asked SQL Interview Q&A 💻📊

1️⃣ Difference between RANK() and DENSE_RANK()?

✅ RANK() skips numbers after ties
✅ DENSE_RANK() does not skip numbers

Example: 95, 95, 90
RANK() → 1,1,3
DENSE_RANK() → 1,1,2

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2️⃣ What is a Window Function?

📈 Performs calculations across rows without grouping them into one row.

Examples:
✔️ ROW_NUMBER()
✔️ RANK()
✔️ LEAD()
✔️ LAG()

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3️⃣ ROW_NUMBER() vs RANK()?

🔢 ROW_NUMBER() gives unique numbers to every row.
🔢 RANK() gives same rank to duplicate values.

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4️⃣ What is a Stored Procedure?

⚙️ A saved SQL query that can be reused anytime.

Benefits:
✅ Reusable
✅ Faster execution
✅ Better security

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5️⃣ WHERE vs GROUP BY?

📌 WHERE filters rows
📌 GROUP BY groups rows for aggregation

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