I applied through a job board, likely Glassdoor. A recruiter contacted me and provided a set of four HackerRank questions that I had one hour to complete.

The first two questions were algorithm-based, and the latter two were SQL.

I solved both algorithm questions in about 40-45 minutes, with what I believe was one broken test out of approximately 20.

My SQL answers, however, did not work well with HackerRank's SQL interpreter. I likely used syntax that is not available on every RDBMS, causing HackerRank to reject my submission.

Afterwards, I checked my answer on an online Oracle SQL interpreter, and it was correct.

I considered explaining my answer in an email to the recruiter, but I never heard back from them.

Some individuals have had positive experiences with HackerRank and other online judges. However, in my opinion, online judges are quite unforgiving as they allow no room for error.

Regarding the DB question, I don't remember the exact question, but it was something like finding the row with the maximum value within a filtered group. The group had to be composed of multiple tables.