THE CLOUD EXPEDITION! · Chapter 6

Past Meets Present Meets Shared

Chronos and Marina lock eyes. My time travel... he begins. ...plus my shared ecosystem data... she finishes. ONE QUERY. They turn to you in unison. This is the Avengers moment — two paradigms, combined for the first time. Combine Time Travel + Shared Data — joining historical snapshots with live shared databases.

Your task

Correlate storm damage with ecosystem readings. First compute the population change per district (version 1 vs current), then match each district to its ecosystem readings. Each district has several readings, so average them: return <b>district</b>, <b>pop_change</b>, <b>avg_temperature</b>, and <b>avg_water_quality</b> — biggest absolute population changes first. Tables: <code>dbquacks_living_lake.pond_census</code> (Ducklake, version 1 = pre-storm), <code>dbquacks_marina_lake.ecosystem_readings</code> (shared, has <code>pond_name</code>, <code>temperature</code>, <code>water_quality</code> — district names match pond_name).<br><br><b>Re-attach if needed:</b><ul><li><code>dbquacks_marina_lake</code> → <code>md:_share/marina_lake_db/3be07852-dfce-4b29-b415-99c9f7fdcc6a</code></li></ul>

Start level 17 →

DuckDB docs for this lesson