Exercise: Solve a complex question using CTEs and/or subqueries

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Category ==> SQL  (115 exercises)
Topic ==> Derived tables and CTEs  (7 exercises)
Level ==> Harder than average
Course ==> Advanced SQL
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First run the script shown above to generate the Doctor Who training database.

Create a query which lists the David Tennant episodes for which none of the enemies appear in any non-David Tennant episodes:

Episode list

The first few of the 31 David Tennant episodes which don't share any enemies with any other non-Tennant episodes.


There are probably hundreds of ways to do this in SQL, and the answer given doesn't claim to use a particularly efficient one.

Optionally, save this query as Tennant only, then close it down. 

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