I was referred by an FB employee. An HR representative connected with me within a week and asked about my experience. They were very happy with my profile, and then came the online coding round using CoderPad. I was asked 4 SQL and 3 Python questions. I believe there are usually 5 SQL and 5 Python questions, but depending on time constraints, they ask as many as possible. I did very well in SQL and struggled with Python. However, I cleared the interview.

The reason I was sent to the next round was that I shared my thought process at each level. For example, when they showed me the ERD, I mentioned what the facts and dimensions were. I also noted that there should be one more dimension for promotions, essentially giving my views on potential improvements.

With SQL, I always started by giving answers logically, always providing the business context. For instance, one question asked to find the percentage increase in revenue due to promotions. Without even looking at the ERD, I directly stated that promo_id should be in the fact table ('sales') and the price of the product should be in the dimensions. I asked the interviewer what exactly they meant by 'revenue,' inquiring if there were any additional earnings for a product.

I will be traveling for my onsite interview soon and will update my comment once it's completed.

SQL:

1. Percentage increase in revenue compared to promoted and non-promoted products.
2. Product classes with the highest number of transactions.
3. Count of customers who bought two item types (A, B).
4. Don't remember.

Python:

1. Average length of letters to words.
2. Parse an IP address (This is a favorite Facebook question).
3. For the input [[A],[A,B],[A,C],[B,D],[C,A]], find the alphabet with the highest number of neighbors. (Wasn't able to solve because of a time limit, but the interviewer indicated understanding of the conveyed approach. I provided an algorithm for what I would have done).