I was contacted by the recruiter, and the initial interview was based on basic questions about experience.

For SQL, the topics covered were: UNION vs UNION ALL, Window functions, HAVING & GROUP BY.

For Python, the questions focused on basic concepts of:

• Lists
• Maps
• Linked Lists
• Sets (such as their purpose and whether they can contain duplicate values).

Moving on to the phone screening round, it was a 60-minute session with 5 SQL and 5 Python questions.

I was able to solve 3 questions of each type but went 5-7 minutes over the allotted time. The questions are time-consuming, so practice is key.

The recruiter was helpful. Also, try to explain your code as you go.

SQL

Q1. Find the IDs of the top 5 customers, ordered by average payment per book made by the people they invited.

Q2. Find the total number of authors registered with the bookstore. What percentage of them have a website URL that contains ".com", and what percentage never made a sale?

Q3. What was the total value of sales and the number of unique paying customers, grouped and sorted in descending order by payment type?

Python

Q1. Write a function that returns the smallest non-negative number which can be generated by using all the digits with odd values of a given number.

Q2. The bookstore gathered a list of customer comments from each shop location and wants to find the most common comment across all locations (ignoring duplicates from the same location). If multiple comments appear the same number of times, return any one of them.

Q3. Given a list of workshops, return the largest number of classes that were hosted in total across any 2 consecutive years that had at least one workshop each.