SQL Learning - Part 5 - Testing for a Real Life Interview

 Now the previous test looked a lot like you would get in a university exam. But the world is not a university and we are not sitting an exam. I am gonna interview for a company, and I certainly won't be expected to dwell on the usage (or not) of SQL. So here's what Jarvis came up with when asked for impersonating a real life interviewer taking an interview of a nervous young chap in horn rimmed glasses with perspiration beading on his forehead and shaking fingers clasped around a glass of water that was only too cold for his bony little hands with veins bulging with tense blood pressure.

Week 1: SQL Basics and Database Design

1. Can you explain a scenario where you had to retrieve data from multiple tables using joins to perform analysis?

2. Describe a situation where you had to design a new database schema to accommodate changing business requirements.

3. How would you handle duplicate records in a database when performing data analysis or generating reports?

4. Share an example of using SQL to extract insights from transactional data to support business decision-making.

5. Discuss a case where you had to optimize a slow-performing SQL query to improve data retrieval speed.

Week 2: DML and DDL

1. Describe a project where you had to import and transform data from external sources into a database for analysis.

2. How would you approach modifying an existing database structure to incorporate additional data fields requested by stakeholders?

3. Provide an example of using SQL to perform data cleansing or data quality checks on a large dataset.

4. Explain how you would handle database backups and recovery to ensure data integrity and minimize downtime.

5. Share a situation where you had to work with database administrators to address security concerns or implement access controls.

Week 3: Joins and Aggregation

1. Can you describe a scenario where you used SQL joins to combine data from multiple sources to create a comprehensive analysis?

2. How would you approach calculating key performance metrics, such as customer retention rate or average order value, using SQL queries?

3. Discuss a situation where you had to aggregate data at different levels (e.g., daily, monthly) for reporting purposes.

4. Share an example where you had to use SQL to identify patterns or trends in customer behavior based on transactional data.

5. Explain how you would handle missing or incomplete data when performing aggregations or analysis using SQL.

Week 4: Subqueries

1. Describe a scenario where you used subqueries to retrieve specific subsets of data for further analysis.

2. How would you approach creating complex queries that require multiple levels of nesting using subqueries?

3. Provide an example of using subqueries to identify outliers or anomalies in a dataset.

4. Explain a situation where you had to use correlated subqueries to filter or join data based on related conditions.

5. Share a case where you used subqueries to perform data validations or data reconciliation across different tables.

Week 5: Views

1. Can you discuss a situation where you created views to simplify complex SQL queries for reporting or analysis purposes?

2. How would you approach updating or modifying data through views while ensuring data integrity and security?

3. Provide an example of using views to create virtual tables that combine data from multiple tables to support specific reporting requirements.

4. Explain a scenario where you used views to provide restricted access to specific data subsets for different user roles or departments.

5. Share a case where you used views to standardize and streamline data access for reporting or analytics purposes.