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PostGIS that stays fast when the table grows
PostGIS / SQLWrite the four spatial joins that cover most production PostGIS work — aggregate-per-area, within-a-distance, nearest-neighbour and point-in-polygon — in the index-assisted form, in metres on geography, with NULL-safe logic that keeps the rows a report is about.
Four spatial-SQL patterns on real tables — the outer join that keeps empty rows, the DWithin an index can answer, the KNN that finds the nearest, and a containment audit — each written the way the planner can use.
4 steps · ~2.5 h · 920 XP
Begins with Docks and bikes per borough, in one query
Start: Docks and bikes per borough, in one queryShow the 4 stepsHide the steps
- Docks and bikes per borough, in one querybeginnerDifficulty: beginner~25 min
- Which ports are within 25 km of a capital?intermediateDifficulty: intermediate~35 min
- Redirect the rider at an empty dockintermediateDifficulty: intermediate~40 min
- Are these country polygons fit to assign cities to?advancedDifficulty: advanced~45 min