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Interview questions
Categorised questions with detailed answers. Filter by category and difficulty.
All
.NET
40
React
13
SQL
12
System Design
28
React
Easy
Props vs State in React — the real difference
React
Medium
useEffect dependency array in React — the exhaustive rules
React
Easy
What is JSX in React? How is it different from HTML?
React
Easy
useState vs useReducer in React — when to use which
React
Medium
Controlled vs Uncontrolled components in React — with examples
React
Medium
React keys — why they matter and the most common mistake
React
Medium
useMemo vs useCallback in React — when each one actually helps
React
Medium
React Context vs Redux — when each one makes sense
React
Hard
Server Components vs Client Components in Next.js 15
React
Hard
React Suspense and concurrent rendering — the modern data-loading pattern
SQL
Easy
INNER JOIN vs LEFT JOIN in SQL — the real difference, with examples
SQL
Easy
SELECT vs SELECT DISTINCT in SQL — when to use which
SQL
Easy
WHERE vs HAVING in SQL — what is the actual difference?
SQL
Medium
GROUP BY in SQL — explained with real-world examples
SQL
Medium
Subquery vs JOIN in SQL — performance and readability tradeoffs