Mastering Oracle SQL Interview Questions: Tips and Answers

Introduction:

• Briefly introduce the importance of Oracle SQL in database management and the significance of being well-prepared for SQL-related interviews.

Commonly Asked Oracle SQL Interview Questions:

1. Difference Between RANK and DENSE_RANK Functions:

   • Explanation of both functions and their distinctions.

2. Purpose of the UNION Operator:

   • Explanation of how the UNION operator combines query results.

3. Advantages of Using Indexes:

   • Discussion on the benefits of using indexes in a database.

4. Difference Between WHERE and HAVING Clauses:

   • Clarification on the distinctions between the WHERE and HAVING clauses.

5. Oracle Query Optimizer:

   • Explanation of how the Oracle Query Optimizer determines query execution plans.

6. ROW-level vs. STATEMENT-level Triggers:

   • Comparison between ROW-level and STATEMENT-level triggers.

7. Function of COMMIT and ROLLBACK Statements:

   • Explanation of how COMMIT and ROLLBACK statements affect transactions.

8. Advantages of Using Bind Variables:

   • Discussion on the benefits of using bind variables in Oracle SQL.

9. Difference Between VARCHAR and VARCHAR2 Data Types:

   • Comparison between VARCHAR and VARCHAR2 data types in Oracle.

10. Database Roles and Privileges:

    • Explanation of database roles, privileges, and their management in Oracle SQL.

Oracle SQL Practical Application Questions:

1. Finding Average Salary by Department:

   • SQL query to find the average salary of employees within each department.

2. Identifying Employees Earning More than Managers:

   • SQL query to find employees who earn more than their managers.

3. Updating Order Status:

   • SQL query to update the status column of the orders table based on conditions.

4. Retrieving User Login Information:

   • SQL query to retrieve the date and time of the last 10 logins for a specific user.

5. Finding Top Five Highest-Rated Products:

   • SQL query to retrieve the top five highest-rated products based on customer reviews.

6. Calculating Total Revenue by Customer:

   • SQL query to calculate the total revenue generated by each customer in the last three months.

7. Determining Percentage Contribution of Products:

   • SQL query to calculate the percentage of total sales each product contributes to overall revenue.

8. Finding Employees Not Assigned to Projects:

   • SQL query to find the names of employees not assigned to any project.

9. Identifying Most Common Employee Names:

   • SQL query to find the five most common names in the Employee table.

10. Enforcing Role-Based Insertion:

    • SQL trigger to ensure only users with the manager role can insert rows into the performance_reviews table.

Conclusion:

• Summarize key points covered in the blog post and encourage readers to practice Oracle SQL interview questions to enhance their skills.

Closing Thoughts:

• Offer additional resources or tips for mastering Oracle SQL and preparing for interviews.