Case 7: And Then There Were None

On a remote island off the Devon coast, ten strangers are invited to a grand mansion by a mysterious host who never appears. On their first evening, a gramophone recording accuses each guest of a past crime.

Soon after, one of them dies suddenly—and then another. Panic sets in as they realize they are being killed one by one, following a grim nursery rhyme displayed in each room.

Your mission: Use SQL to track each guest's actions, cross-reference accusations and reveal how justice was chillingly delivered on Soldier Island.

About this case

Based on And Then There Were None (Agatha Christie, 1939). Ten strangers are lured to a remote island and accused of past crimes by a mysterious voice. As they are killed one by one in a pattern following a grim nursery rhyme, suspicion turns inward—one of them must be the killer.

What you'll practise

This challenging case requires advanced SQL mastery:

Complex WHERE logic combining multiple conditions and time filters
ORDER BY for precise sequencing of deaths and accusations
Pattern recognition across multiple data points
Eliminating suspects systematically using sophisticated query logic

The database

You'll query the suspect_info table, tracking each guest's past crimes, their movements on the island, the order of deaths, and the accusations made against them. The data is abundant but the pattern is subtle.

Difficulty

Advanced. This is one of the most complex cases. Requires mastery of SQL filtering, pattern recognition, and the ability to think through impossible scenarios logically using data.