如何在WHERE子句中使用ST_Intersects

问题描述

我想知道如何执行以下操作

WHERE NOT ST_Intersects(dataSource.LIDARDataAsSinglePolygon,geom)

查询：

  def exec(self,geometryAsGeoJSONObjectAsString,geom):
    query="""
    WITH dataSource As(
    SELECT DISTINCT
        ST_AsGeoJSON(ST_Union(ST_GeomFromGeoJSON(feature->>'geometry'))) As LIDARDataAsSinglePolygonUsingST_UnionAsGeoJSONInEPSG4326,
        ST_AsText(ST_Union(ST_GeomFromGeoJSON(feature->>'geometry'))) As LIDARDataAsSinglePolygon
        )
    FROM 
        (SELECT json_array_elements('{geometryAsGeoJSONObjectAsString}'::json->'features') AS feature) a WHERE NOT ST_Intersects(dataSource.LIDARDataAsSinglePolygon,geom);
    """.format(geometryAsGeoJSONObjectAsString=geometryAsGeoJSONObjectAsString)
    print(query)
    data = self.connection.query(query,[])
    # print(data)        
    return data

小提琴：

https://dbfiddle.uk/?rdbms=postgres_12&fiddle=8dc0ccc1017a220098022131e8d41063

---

解决方案

您最有可能尝试将ST_Intersects与表达式的别名一起使用，而不是与列或几何图形一起使用。您的逻辑是颠倒的：您需要首先解析和转储要素集合中的几何，然后应用过滤器，而不是反过来：

WITH datasource (feature) AS (
 SELECT json_array_elements('{json_string}'::json->'features')  
)
SELECT 
  ST_AsGeoJSON(ST_Union(ST_GeomFromGeoJSON(feature->>'geometry'))),
  ST_AsText(ST_Union(ST_GeomFromGeoJSON(feature->>'geometry')))
FROM datasource
WHERE NOT ST_Intersects(ST_GeomFromGeoJSON(feature->>'geometry'),'{a geometry}');