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Bài tập

Reigning champions by gender and event

In the previous exercise, you partitioned by gender to ensure that data about one gender doesn't get mixed into data about the other gender. If you have multiple columns, however, partitioning by only one of them will still mix the results of the other columns.

Hướng dẫn

100 XP
  • Return the previous champions of each year's events by gender and event.