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Database / DuckDB Interview questions

What is the spatial extension used for in DuckDB?

The spatial extension adds geospatial data types (like points, lines, and polygons) and a set of geospatial functions (distance calculations, spatial joins, geometry operations) to DuckDB, letting it handle location-based analytical queries alongside standard relational and columnar data.

INSTALL spatial;
LOAD spatial;

SELECT name, ST_Distance(location, ST_Point(-122.4, 37.7)) AS distance
FROM stores
ORDER BY distance
LIMIT 10;

It also adds the ability to read common geospatial file formats (like Shapefiles and GeoJSON) directly, similar to how DuckDB reads Parquet or CSV natively. This makes DuckDB a practical tool for geospatial analysis, finding the nearest stores to a location, computing overlaps between geographic regions, without needing a dedicated, heavier-weight GIS-specific database just for that part of an analytical workflow.

The spatial extension adds:
The spatial extension can also read directly from formats like:

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