1) Coding question in a lang of your desire, here it is: Given the following class (JAVA): class Role { String title, LocalDate effectiveFrom } You need to calculate what role an employee had per a given set of dates, can be multiple roles of course. Need to implement the following function: Map rolesByDates(List history, List dates) Note that the history list is sorted by the effectiveFrom property in descending order. Here's the main function: public static void main(String[] args) { List history = Arrays.asList( new Role("Team Leader", LocalDate.of(2020, 8, 1)), new Role("Fullstack developer", LocalDate.of(2016, 5, 15)), new Role("Frontend developer", LocalDate.of(2015, 11, 17)) ); List dates = Arrays.asList( LocalDate.of(2021, 1, 1), LocalDate.of(2014, 1, 1), LocalDate.of(2016, 6, 1) ); Map rolesByDates = rolesByDates(history, dates); rolesByDates.forEach((key, value) -> System.out.println("date = " + key + ", role = " + value.getTitle())); } 2) Given a system that generates surveys (similar to google forms), need to represent its data in high level, like technical design on how to implement such data structure, only data. 3) Differences between SQL / NO-SQL, an easy question on sql syntax, related to the previous question and on which db it will be better to represent it.