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  • Basic
  • Joins and Subqueries
  • Aggregates

Joins and Subqueries Begin!

This category deals primarily with a foundational concept in relational database systems: joining. Joining allows you to combine related information from multiple tables to answer a question.

  1. Retrieve the start times of members' bookings
  2. Work out the start times of bookings for tennis courts
  3. Produce a list of all members who have recommended another member
  4. Produce a list of all members, along with their recommender
  5. Produce a list of all members who have used a tennis court
  6. Produce a list of costly bookings
  7. Produce a list of all members, along with their recommender, using no joins.
  8. Produce a list of costly bookings, using a subquery
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