st_union
How PostGIS runs Dissolve: st_union.
| Engine | PostGIS |
|---|---|
| Tool name | st_union |
| Interface | sql |
| Implements | Dissolve |
| Documentation | Not stated |
| Effects | modifies input: no, network: no |
| Notes | Has an aggregate form. |
| Status | active |
Parameters
| Name | Type | Required | Default | Choices | Note |
|---|---|---|---|---|---|
geom1 | geometry | no | Not stated | Not stated | Not stated |
geom2 | geometry | no | Not stated | Not stated | Not stated |
gridsize | double precision | no | Not stated | Not stated | Not stated |
SQL overloads
-
st_union(geom1 geometry, geom2 geometry) → geometry -
st_union(geom1 geometry, geom2 geometry, gridsize double precision) → geometry -
st_union(geometry) → geometry (aggregate) -
st_union(geometry, gridsize double precision) → geometry (aggregate) -
st_union(geometry[]) → geometry
How it maps to the operation
| Operation parameter | Parameter here | Note |
|---|---|---|
layer | #1 | Not stated |
by | Not stated | Use the aggregate form with GROUP BY the fields. |
Differences from the operation
- Dissolving is the aggregate form, ST_Union(geom) with GROUP BY; the two-argument form unions just two geometries.
Harvested by the postgis harvester from engine version
3.7.0. Names can change when an engine is harvested again.