PostgreSQL Interview Cheat Sheet

1. What is PostgreSQL?

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2. What is a database cluster in PostgreSQL?

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3. What is a schema in PostgreSQL?

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4. What is the difference between a table and a view?

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5. What is a primary key in PostgreSQL?

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6. What is a foreign key?

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7. What data types does PostgreSQL support?

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8. What is the purpose of the SELECT statement?

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9. What is the WHERE clause used for?

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10. What is ORDER BY in PostgreSQL?

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11. What is the LIMIT clause?

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12. What is a UNIQUE constraint?

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13. What is the purpose of the INSERT statement?

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14. What is the difference between DELETE and DROP?

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15. What is a default value in PostgreSQL?

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16. What is the PostgreSQL psql tool used for?

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17. What is the purpose of the SERIAL data type?

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18. What is the difference between TEXT and VARCHAR?

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19. What are ENUM types used for?

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20. What is a CHECK constraint?

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21. What is the purpose of the RETURNING clause in PostgreSQL?

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22. What is the difference between INNER JOIN and FULL OUTER JOIN?

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23. What is a sequence in PostgreSQL?

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24. What is the purpose of the COALESCE function?

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25. What are indexes in PostgreSQL and why are they important?

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26. What is a partial index?

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27. What is a composite index?

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28. What is a materialized view?

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29. What is the difference between DELETE and TRUNCATE in PostgreSQL?

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30. What is the VACUUM operation in PostgreSQL?

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31. What is the ANALYZE command used for?

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32. What is the difference between a function and a stored procedure in PostgreSQL?

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33. What is PostgreSQL’s JSONB data type?

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34. What are foreign data wrappers (FDW)?

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35. What is the purpose of the EXPLAIN command?

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36. What is PostgreSQL’s MVCC and how does it enable concurrent reads and writes?

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37. What is a tuple in PostgreSQL?

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38. What is a transaction ID and why is wraparound dangerous?

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39. What is VACUUM FULL and how does it differ from regular VACUUM?

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40. What is the visibility map in PostgreSQL?

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41. What is an index-only scan?

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42. What is the difference between B-Tree, GIN, and GiST indexes?

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43. When would you use a BRIN index?

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44. What is the purpose of pg_stat_activity?

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45. What is a CTE and why use it?

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46. What is the difference between a CTE and a subquery?

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47. How do recursive CTEs work?

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48. What are dead tuples and why do they accumulate?

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49. How does PostgreSQL handle deadlocks?

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50. What is a tablespace?

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