Chamber 30 · Twin Currents

Twin Proof

Self-join plus EXISTS

Self JOINEXISTS+165 XP

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Briefing

Combine the floor's tools: apprentices who have a mentor and also resurfaced at least once.

Return apprentice name for divers with a mentor (self-join) who EXISTS in beacon_log, ordered by name.

Keep the self-join, then AND EXISTS (beacon_log for apprentice.id).

Chamber schema

divers3 cols

Divers with mentors

idnamementor_id

beacon_log3 cols

Resurface pings

iddiver_idsurfaced_on

chamber_30.sql

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