builtins: implement ST_Points

docs/generated/sql/functions.md

@@ -1541,6 +1541,8 @@ calculated, the result is transformed back into a Geography with SRID 4326.</p>
 <tr><td><a name="st_pointonsurface"></a><code>st_pointonsurface(geometry: geometry) &rarr; geometry</code></td><td><span class="funcdesc"><p>Returns a point that intersects with the given Geometry.</p>
 <p>This function utilizes the GEOS module.</p>
 </span></td></tr>
+<tr><td><a name="st_points"></a><code>st_points(geometry: geometry) &rarr; geometry</code></td><td><span class="funcdesc"><p>Returns all coordinates in the given Geometry as a MultiPoint, including duplicates.</p>
+</span></td></tr>
 <tr><td><a name="st_polyfromtext"></a><code>st_polyfromtext(str: <a href="string.html">string</a>, srid: <a href="int.html">int</a>) &rarr; geometry</code></td><td><span class="funcdesc"><p>Returns the Geometry from a WKT or EWKT representation with an SRID. If the shape underneath is not Polygon, NULL is returned. If the SRID is present in both the EWKT and the argument, the argument value is used.</p>
 </span></td></tr>
 <tr><td><a name="st_polyfromtext"></a><code>st_polyfromtext(val: <a href="string.html">string</a>) &rarr; geometry</code></td><td><span class="funcdesc"><p>Returns the Geometry from a WKT or EWKT representation. If the shape underneath is not Polygon, NULL is returned.</p>

pkg/geo/geomfn/unary_operators.go

@@ -148,3 +148,61 @@ func dimensionFromGeomT(geomRepr geom.T) (int, error) {
 		return 0, errors.AssertionFailedf("unknown geometry type: %T", geomRepr)
 	}
 }
+
+// Points returns the points of all coordinates in a geometry as a multipoint.
+func Points(g geo.Geometry) (geo.Geometry, error) {
+	t, err := g.AsGeomT()
+	if err != nil {
+		return geo.Geometry{}, err
+	}
+	layout := t.Layout()
+	if gc, ok := t.(*geom.GeometryCollection); ok && gc.Empty() {
+		layout = geom.XY
+	}
+	points := geom.NewMultiPoint(layout).SetSRID(t.SRID())
+	iter := geo.NewGeomTIterator(t, geo.EmptyBehaviorOmit)
+	for {
+		geomRepr, hasNext, err := iter.Next()
+		if err != nil {
+			return geo.Geometry{}, err
+		} else if !hasNext {
+			break
+		} else if geomRepr.Empty() {
+			continue
+		}
+		switch geomRepr := geomRepr.(type) {
+		case *geom.Point:
+			if err = pushCoord(points, geomRepr.Coords()); err != nil {
+				return geo.Geometry{}, err
+			}
+		case *geom.LineString:
+			for i := 0; i < geomRepr.NumCoords(); i++ {
+				if err = pushCoord(points, geomRepr.Coord(i)); err != nil {
+					return geo.Geometry{}, err
+				}
+			}
+		case *geom.Polygon:
+			for i := 0; i < geomRepr.NumLinearRings(); i++ {
+				linearRing := geomRepr.LinearRing(i)
+				for j := 0; j < linearRing.NumCoords(); j++ {
+					if err = pushCoord(points, linearRing.Coord(j)); err != nil {
+						return geo.Geometry{}, err
+					}
+				}
+			}
+		default:
+			return geo.Geometry{}, errors.AssertionFailedf("unexpected type: %T", geomRepr)
+		}
+	}
+	return geo.MakeGeometryFromGeomT(points)
+}
+
+// pushCoord is a helper function for PointsFromGeomT that appends
+// a coordinate to a multipoint as a point.
+func pushCoord(points *geom.MultiPoint, coord geom.Coord) error {
+	point, err := geom.NewPoint(points.Layout()).SetCoords(coord)
+	if err != nil {
+		return err
+	}
+	return points.Push(point)
+}

pkg/geo/geomfn/unary_operators_test.go

@@ -14,6 +14,7 @@ import (
 	"testing"
 
 	"github.com/cockroachdb/cockroach/pkg/geo"
+	"github.com/cockroachdb/cockroach/pkg/geo/geopb"
 	"github.com/stretchr/testify/require"
 )
 
@@ -123,3 +124,60 @@ func TestDimension(t *testing.T) {
 		})
 	}
 }
+
+func TestPoints(t *testing.T) {
+	testCases := []struct {
+		wkt      string
+		expected string
+	}{
+		{"POINT EMPTY", "MULTIPOINT EMPTY"},
+		{"POINT (1 2)", "MULTIPOINT (1 2)"},
+		{"MULTIPOINT EMPTY", "MULTIPOINT EMPTY"},
+		{"MULTIPOINT (1 2, 3 4)", "MULTIPOINT (1 2, 3 4)"},
+		{"LINESTRING EMPTY", "MULTIPOINT EMPTY"},
+		{"LINESTRING (1 2, 3 4)", "MULTIPOINT (1 2, 3 4)"},
+		{"MULTILINESTRING EMPTY", "MULTIPOINT EMPTY"},
+		{"MULTILINESTRING ((1 2, 3 4), (5 6, 7 8))", "MULTIPOINT (1 2, 3 4, 5 6, 7 8)"},
+		{"POLYGON EMPTY", "MULTIPOINT EMPTY"},
+		{"POLYGON ((1 2, 3 4, 5 6, 1 2))", "MULTIPOINT (1 2, 3 4, 5 6, 1 2)"},
+		{"MULTIPOLYGON EMPTY", "MULTIPOINT EMPTY"},
+		{"MULTIPOLYGON (((1 2, 3 4, 5 6, 1 2)), ((7 8, 9 0, 1 2, 7 8)))", "MULTIPOINT (1 2, 3 4, 5 6, 1 2, 7 8, 9 0, 1 2, 7 8)"},
+		{"GEOMETRYCOLLECTION EMPTY", "MULTIPOINT EMPTY"},
+		{"GEOMETRYCOLLECTION (GEOMETRYCOLLECTION EMPTY)", "MULTIPOINT EMPTY"},
+		{
+			`GEOMETRYCOLLECTION (
+				LINESTRING(1 1, 2 2),
+				POINT(1 1),
+				GEOMETRYCOLLECTION(
+					MULTIPOINT(2 2, 3 3),
+					GEOMETRYCOLLECTION EMPTY,
+					POINT(1 1),
+					MULTIPOLYGON(((1 2, 2 3, 3 4, 1 2))),
+					LINESTRING(3 3, 4 4),
+					GEOMETRYCOLLECTION(
+						POINT(4 4),
+						MULTIPOLYGON (EMPTY, ((1 2, 3 4, 5 6, 1 2), (2 3, 3 4, 4 5, 2 3)), EMPTY),
+						POINT(5 5)
+					)
+				),
+				MULTIPOINT EMPTY
+			)`,
+			"MULTIPOINT (1 1, 2 2, 1 1, 2 2, 3 3, 1 1, 1 2, 2 3, 3 4, 1 2, 3 3, 4 4, 4 4, 1 2, 3 4, 5 6, 1 2, 2 3, 3 4, 4 5, 2 3, 5 5)",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.wkt, func(t *testing.T) {
+			srid := geopb.SRID(4000)
+			g, err := geo.ParseGeometryFromEWKT(geopb.EWKT(tc.wkt), srid, true)
+			require.NoError(t, err)
+
+			result, err := Points(g)
+			require.NoError(t, err)
+			wkt, err := geo.SpatialObjectToWKT(result.SpatialObject(), 0)
+			require.NoError(t, err)
+			require.EqualValues(t, tc.expected, wkt)
+			require.EqualValues(t, srid, result.SRID())
+		})
+	}
+}

pkg/sql/logictest/testdata/logic_test/geospatial

@@ -2632,6 +2632,26 @@ Square (left)                             Polygon             ST_Polygon
 Square (right)                            Polygon             ST_Polygon             2     2     2     5     1
 Square overlapping left and right square  Polygon             ST_Polygon             2     2     2     5     1
 
+query TT
+SELECT
+  dsc,
+  ST_AsEWKT(ST_Points(geom))
+FROM geom_operators_test
+ORDER BY dsc
+----
+Empty GeometryCollection                  MULTIPOINT EMPTY
+Empty LineString                          MULTIPOINT EMPTY
+Empty Point                               MULTIPOINT EMPTY
+Faraway point                             MULTIPOINT (5 5)
+Line going through left and right square  MULTIPOINT (-0.5 0.5, 0.5 0.5)
+NULL                                      NULL
+Nested Geometry Collection                MULTIPOINT (0 0)
+Point middle of Left Square               MULTIPOINT (-0.5 0.5)
+Point middle of Right Square              MULTIPOINT (0.5 0.5)
+Square (left)                             MULTIPOINT (-1 0, 0 0, 0 1, -1 1, -1 0)
+Square (right)                            MULTIPOINT (0 0, 1 0, 1 1, 0 1, 0 0)
+Square overlapping left and right square  MULTIPOINT (-0.1 0, 1 0, 1 1, -0.1 1, -0.1 0)
+
 query TTTT
 SELECT
   a.dsc,

pkg/sql/sem/builtins/geo_builtins.go

@@ -1775,6 +1775,23 @@ Flags shown square brackets after the geometry type have the following meaning:
 			tree.VolatilityImmutable,
 		),
 	),
+	"st_points": makeBuiltin(
+		defProps(),
+		geometryOverload1(
+			func(ctx *tree.EvalContext, g *tree.DGeometry) (tree.Datum, error) {
+				points, err := geomfn.Points(g.Geometry)
+				if err != nil {
+					return nil, err
+				}
+				return tree.NewDGeometry(points), nil
+			},
+			types.Geometry,
+			infoBuilder{
+				info: "Returns all coordinates in the given Geometry as a MultiPoint, including duplicates.",
+			},
+			tree.VolatilityImmutable,
+		),
+	),
 	"st_exteriorring": makeBuiltin(
 		defProps(),
 		geometryOverload1(