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Database and SQL Mock Test – Free Online Assessment Version 1.2

Database and SQL intermediate mock test with advanced queries and performance questions

The Database & SQL Mock Test v1.2 is an intermediate-level practice quiz designed to help learners apply database concepts and SQL knowledge in more practical and performance-oriented scenarios. This version builds upon the foundations covered in v1.0 and v1.1, focusing on real-world SQL usage commonly expected in technical interviews and professional environments.

This quiz emphasizes advanced querying techniques, subqueries, joins, indexing, transactions, and performance considerations that are essential for students, developers, and IT professionals working with relational databases.

Version 1.2 includes Questions 101–150, extending the difficulty level while maintaining clear and structured multiple-choice questions for effective learning and assessment.

📌 What This Version Covers

  • Subqueries (scalar, correlated, nested)
  • EXISTS vs IN comparisons
  • Advanced JOIN scenarios (self join, cross join)
  • Indexing concepts and query performance
  • Clustered vs non-clustered indexes
  • Transactions, COMMIT and ROLLBACK
  • Isolation levels and concurrency control
  • Database locking and consistency
  • Views, triggers, and stored procedures
  • Normalization and real-world SQL scenarios

✨ Quiz Features

  • 📝 50 intermediate-level multiple-choice questions (Q101–Q150)
  • ⏱️ Time-based test environment
  • 📊 Instant score calculation and result display
  • 🔁 Retake option for continuous improvement
  • 🎯 Designed for interview preparation and skill validation

👤 Who Should Take This Test?

  • Students advancing their SQL and database knowledge
  • Fresh graduates preparing for technical interviews
  • Junior developers and database professionals
  • IT professionals revising performance-oriented SQL concepts
  • Anyone aiming to move from basic to intermediate SQL proficiency

ℹ️ Version Information

  • Current Version: 1.2
  • Question Range: Q101–Q150
  • Level: Intermediate
  • Future Updates: Advanced SQL (v2.0), complex joins, window functions, optimization strategies, and analytics-based performance insights

💡 This quiz is designed as a practical self-assessment and learning tool. Repeating the test will help users improve query logic, performance awareness, and confidence in handling real-world database scenarios.

1 / 50

Q150. Which SQL concept improves query execution plans?

2 / 50

Q149. Which SQL JOIN is used when all records are required?

3 / 50

Q148. Which SQL function returns number of non-NULL values?

4 / 50

Q147. Which SQL statement modifies table structure only?

5 / 50

Q146. Which SQL feature controls concurrent access?

6 / 50

Q145. Which SQL object improves security by hiding columns?

7 / 50

Q144. Which isolation level offers highest data consistency?

8 / 50

Q143. Which SQL command removes duplicate rows from results?

9 / 50

Q142. Which SQL clause limits rows before grouping?

10 / 50

Q141. Which query is best for checking existence of records?

11 / 50

Q140. Which SQL feature ensures durability?

12 / 50

Q139. Which SQL command copies data from one table to another?

13 / 50

Q138. Which database operation is fastest for deleting all rows?

14 / 50

Q137. Which SQL clause restricts groups, not rows?

15 / 50

Q136. Which SQL function converts NULL to a value?

16 / 50

Q135. Which SQL object cannot accept parameters?

17 / 50

Q134. Which SQL feature avoids data redundancy?

18 / 50

Q133. Which index is best for range queries?

19 / 50

Q132. Which SQL command is used to optimize tables?

20 / 50

Q131. Which SQL keyword enforces referential integrity?

21 / 50

Q130. Which clause filters aggregated data?

22 / 50

Q129. Which SQL feature ensures atomicity?

23 / 50

Q128. Which JOIN is fastest when indexed columns are used?

24 / 50

Q127. Which database object stores metadata?

25 / 50

Q126. Which SQL command renames a column?

26 / 50

Q125. Which SQL function returns current date and time?

27 / 50

Q124. Which SQL clause is executed last in query processing?

28 / 50

Q123. Which SQL statement combines results including duplicates?

29 / 50

Q122. Which key uniquely identifies rows and cannot be NULL?

30 / 50

Q121. Which normalization form removes transitive dependency?

31 / 50

Q120. Which function returns total rows including NULL values?

32 / 50

Q119. Which SQL clause improves performance by limiting rows?

33 / 50

Q118. Which command removes user permissions?

34 / 50

Q117. Which command grants user permissions?

35 / 50

Q116. Which SQL object executes automatically on table events?

36 / 50

Q115. Which SQL object stores precompiled SQL code?

37 / 50

Q114. Which problem occurs when uncommitted data is read?

38 / 50

Q113. Which isolation level prevents phantom reads?

39 / 50

Q112. Which isolation level prevents dirty reads?

40 / 50

Q111. Which command undoes changes in a transaction?

41 / 50

Q110. Which SQL command saves transaction changes permanently?

42 / 50

Q109. Which index allows duplicate values?

43 / 50

Q108. Which index type determines physical data order?

44 / 50

Q107. Which SQL object improves query performance?

45 / 50

Q106. Which JOIN produces a Cartesian product?

46 / 50

Q105. Which JOIN combines a table with itself?

47 / 50

Q104. Which subquery depends on the outer query?

48 / 50

Q103. Which subquery returns only one value?

49 / 50

Q102. Which keyword is used to check existence of rows in a subquery?

50 / 50

Q101. Which SQL query is used inside another query?

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