I applied via the website and received an email from HR to do a phone call with them. the HR was completely nice and easy to speak. After that they arranged another Skype call with one of the manager of the company who was very unprofessional person! After that they invited me to person interview in Berlin with this person again who could asked me from our last call! He asked me some technical questions and doing some coding. the case was very easy and I solved the problem in paper but it was hard to implement it very fast. I tried but I couldnt do it. Also he tried to show his skills to me but fortunately he couldnt do that too! After two weeks they didn't send me any information about the decision!!! I received unofficial answer from one of the employees in the company that they don't like to continue with my application that shows they are so unprofessional.

The whole process was really slow. But the interviewers are really nice. The SQL question is about window function. And the case is used to test your logic, business acumen.