I attended the BlackRock Super Day in San Francisco.

I had four different interviewers and interviewed for about four hours.

Some of the interviewers asked a few investment questions, so make sure you know what the Nasdaq is at and what the difference is between a stock and a bond.

One interviewer asked a very difficult SQL question. I feel that if you can answer this question correctly, you will likely secure a position.

He first posed a relatively easy SQL question. The scenario involved a list of portfolios and a list of portGroups, where a portGroup is essentially a collection of portfolios. He requested that you create a single table to store data for both. Crucially, he wanted to avoid two separate tables with keys. The goal was to demonstrate the ability to create one table and use both the portfolio number and the portGroup number as a composite primary key.

Next came the challenging part: he asked you to consider a portGroup as the 'parent' of a portfolio (the child). He then requested that you write SQL JOINs to return the parent of the grandparents of a specific portfolio.

I honestly still don't fully understand it. It makes much more sense with a numerical example. You could also try searching online for similar problems. I suppose the key takeaway is to know how to perform an inner join (and other types of joins).