This was their worst interview experience I ever had. I was sent a test in HackerRank, being told in advance that it would be examining my SQL skills. Opening the test, at the bottom, there was also a prompt saying, "What we will test you on: [...]" where it also referred to SQL alone. I logged into the system and went through my SQL exercises (which I later found I got 75% correct) only to find out at the end of these exercises that I also had some coding exercises, with barely ten minutes left. I reached out to the recruitment team, explaining the situation and providing screenshots of previous correspondence where they told me clearly that I would be tested in SQL only, and they didn't even apologize. I can only imagine how unprofessional the environment internally will be if the recruitment process is so poor.

Complex SQL joins, mostly. Some basic coding.