ST_Collect-PolarDB(PolarDB)-阿里云帮助中心

Merges two or more sfmesh objects into a single sfmesh by combining their nodes.

Syntax

Variant 1: Two sfmesh objects

sfmesh ST_Collect(sfmesh sfmeshObject1, sfmesh sfmeshObject2);

Variant 2: An array of sfmesh objects

sfmesh ST_Collect(sfmesh[] sfmesh_array);

Variant 3: A set of sfmesh objects (aggregate)

sfmesh ST_Collect(setofsfmesh sfmesh_set);

Parameters

Parameter	Description
`sfmeshObject`	An sfmesh object. Variant 1 accepts two sfmeshObject arguments.
`sfmesh_array`	An array of sfmesh objects.
`sfmesh_set`	A set of sfmesh objects used as aggregate input in Variant 3.

Return value

Returns an sfmesh object containing the merged nodes of all input objects.

Usage notes

ST_Collect merges sfmesh objects at the node level only. It does not crop and merge the geometries and textures of the input objects.

Examples

Variant 1: Merge two sfmesh objects directly

WITH tmp AS
(
    SELECT num, the_mesh
    FROM t_mesh
    WHERE num IN (1, 3)
)
SELECT a.num, b.num,
     ST_AsText(st_Collect(a.the_mesh, b.the_mesh))
FROM tmp a, tmp b;

Variant 2: Merge an array of sfmesh objects

WITH tmp AS
(
    SELECT num, the_mesh
    FROM t_mesh
    WHERE num IN (1, 3, 13, 14)
)
SELECT a.num, b.num,
    ST_AsText(st_Collect(ARRAY[a.the_mesh, b.the_mesh]))
FROM tmp a, tmp b;

Variant 3: Aggregate all sfmesh objects in a table

WITH tmp AS
(
     SELECT num, the_mesh
     FROM t_mesh
)
SELECT
     ST_AsText(st_Collect(the_mesh))
FROM tmp;