Wun Code

SQL exam

This exam measures what you've actually learned, in three stages: Easy, Medium, then Hard. Each stage unlocks the next. There are no hints and no ready-made solutions, so it's just you and your code, graded automatically like in the lessons.

  1. Stage 1Locked

    Easy

    • High earnersA filter and a two-column sort8 min
    • Department statsGrouping, an average and a sort10 min
  2. Stage 2Locked

    Medium

    • Employees without projectsA left join or a subquery12 min
    • Hours per projectA join and grouping, with zero instead of NULL14 min
  3. Stage 3Locked

    Hard

    • Top earner in each departmentThe top of each group, ties included18 min
    • Above the department averageA correlated subquery or WITH20 min