SQL Interview Questions

Q1 What is the difference between WHERE and HAVING clause? ✓ Answered → Q2 Explain different types of JOINs in SQL. ✓ Answered → Q3 What is the difference between INNER JOIN and LEFT JOIN? ✓ Answered → Q4 What is GROUP BY clause? ✓ Answered → Q5 What is the difference between UNION and UNION ALL? ✓ Answered → Q6 What are aggregate functions in SQL? ✓ Answered → Q7 What is a subquery? ✓ Answered → Q8 What is correlated subquery? ✓ Answered → Q9 What is the difference between DELETE and TRUNCATE? ✓ Answered → Q10 What is the difference between DROP and TRUNCATE? ✓ Answered → Q11 What is a primary key? ✓ Answered → Q12 What is a foreign key? ✓ Answered → Q13 What is normalization? ✓ Answered → Q14 Explain different normal forms. ✓ Answered → Q15 What is denormalization? ✓ Answered → Q16 What is an index and why is it used? ✓ Answered → Q17 What is the difference between clustered and non-clustered index? ✓ Answered → Q18 What is a composite key? ✓ Answered → Q19 What is a unique constraint? ✓ Answered → Q20 What is a view? ✓ Answered →