Important #SQL concepts to master:
- Joins (inner, left, right, full)
- Group By vs Where vs Having
- Window functions (ROW_NUMBER, RANK, DENSE_RANK)
- CTEs (Common Table Expressions)
- Subqueries and nested queries
- Aggregations and filtering
- Indexing and performance basics
- NULL handling
Interview Tips:
- Focus on writing clean, readable queries
- Explain your logic clearly don’t just jump to #code
- Always test for edge cases (empty tables, duplicate rows)
- Practice optimization: how would you improve performance?
Post #2090
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