I appeared for the Data Engineer phone screen interview last week. I had applied for the job on the FB site and got a call from recruiter. Recruiter was very helpful and provided lots of information and prep material. He had already mentioned that I will have to atleast solve 3 SQL and 3 python questions to make it to the second round.
Format of the interview was 5 min intro, 25 mins SQL questions and 25 mins Python. In this time 5 SQL questions and 5 python questions would be given to you one by one. that is if you solve 1st question then only you will be given second question.
I chose SQL first when I was asked which once I wanted to do first.
SQL questions :
I had to run the queries in Postgres SQL. I had only practiced using Oracle , though Postgres sql supports ANSI SQL. Pay close attention to the use of CAST fuction as I had to use it to get the desired result and cast the demoninator.
The questions were related to sum and avg of the products database and they were to be solved using case statements. I was only able to solve 3 quesitons
Python :
I was able to solve only 2 questions. I was stuck in the edge cases in the second question but eventually took lots of time to solve it. 2 questions I faced were very simple.
- Return total number of times given character appears in the given string
- Replace None value with the previous number in the given array.
Time management is the key. Understand the problem first, think about the edge cases before wtiting the code and then start.
Try to remain calm and try not to get any hints from interviewer. Best of luck to anyone who will be interviewing for DE position