ST_SRID — Returns the spatial reference identifier for a topogeometry.
integer ST_SRID(topogeometry tg);
Returns the spatial reference identifier of the topology containing the TopoGeometry.
The identifier is recorded for the topology when it is created and refers to an entry in 4.5절. “SPATIAL_REF_SYS 테이블과 공간 참조 시스템”.
Availability: 3.2.0
Return the SRID of a TopoGeometry stored in the ri_topo topology.
SELECT topology.ST_SRID(topo) AS srid FROM ri.roads WHERE road_name = 'Unknown';
srid ------ 3438