70 lines
2.0 KiB
SQL
70 lines
2.0 KiB
SQL
CREATE TABLE geoms (geom geometry);
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-- Create 20x20 square polygons
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WITH coords AS (SELECT * FROM generate_series(0, 19) AS x, generate_series(0, 19) AS y)
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INSERT INTO geoms
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SELECT ST_Square(1.0, x, y, ST_MakePoint(0, 0))
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FROM coords;
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WITH u AS (SELECT ST_Union(geom) AS g FROM geoms)
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SELECT ST_Area(g), ST_XMin((g)), ST_YMin(g), ST_XMax(g), ST_YMax(g) from u;
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-- NOTE: using gridSize > 0 requires GEOS-3.9 or higher
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WITH u AS (SELECT ST_Union(geom, -1.0) AS g FROM geoms)
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SELECT ST_Area(g), ST_XMin((g)), sT_YMin(g), ST_XMax(g), ST_YMax(g) from u;
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TRUNCATE TABLE geoms;
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-- Empty table
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SELECT ST_Union(geom) IS NULL FROM geoms;
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-- NULLs
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INSERT INTO geoms (geom) VALUES (NULL), (NULL), (NULL), (NULL), (NULL);
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SELECT ST_Union(geom) IS NULL FROM geoms;
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-- Add empty point
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INSERT INTO geoms SELECT ST_GeomFromText('POINT EMPTY') AS geom;
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SELECT ST_AsText(ST_Union(geom)) FROM geoms;
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-- Add empty polygon
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INSERT INTO geoms SELECT ST_GeomFromText('POLYGON EMPTY') AS geom;
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SELECT ST_AsText(ST_Union(geom)) FROM geoms;
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-- Test in parallel mode
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TRUNCATE TABLE geoms;
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SET force_parallel_mode = on;
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SET parallel_setup_cost = 0;
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SET parallel_tuple_cost = 0;
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SET min_parallel_table_scan_size = 0;
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SET max_parallel_workers_per_gather = 4;
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WITH coords AS (SELECT * FROM generate_series(0, 19) AS x, generate_series(0, 19) AS y)
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INSERT INTO geoms
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SELECT ST_Square(1.0, x, y, ST_MakePoint(0, 0))
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FROM coords;
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WITH u AS (SELECT ST_Union(geom) AS g FROM geoms)
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SELECT ST_Area(g), ST_XMin((g)), ST_YMin(g), ST_XMax(g), ST_YMax(g) from u;
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WITH u AS (SELECT ST_Union(geom, -1.0) AS g FROM geoms)
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SELECT ST_Area(g), ST_XMin((g)), sT_YMin(g), ST_XMax(g), ST_YMax(g) from u;
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TRUNCATE TABLE geoms;
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SELECT ST_Union(geom) IS NULL FROM geoms;
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INSERT INTO geoms (geom) VALUES (NULL), (NULL), (NULL), (NULL), (NULL);
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SELECT ST_Union(geom) IS NULL FROM geoms;
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INSERT INTO geoms SELECT ST_GeomFromText('POINT EMPTY') AS geom;
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SELECT ST_AsText(ST_Union(geom)) FROM geoms;
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INSERT INTO geoms SELECT ST_GeomFromText('POLYGON EMPTY') AS geom;
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SELECT ST_AsText(ST_Union(geom)) FROM geoms;
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DROP TABLE geoms;
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