PostgreSQL: Documentation: 10: 7.8. WITH Queries (Common Table Expressions)

• https://www.postgresql.org/docs/10/static/queries-with.html#QUERIES-WITH-SELECT
• WITH provides a way to write auxiliary statements for use in a larger query. These statements, which are often referred to as Common Table Expressions or CTEs, can be thought of as defining temporary tables that exist just for one query. Each auxiliary statement in a WITH
  clause can be a SELECT, INSERT, UPDATE, or DELETE; and the WITH clause itself is attached to a primary statement that can also be a SELECT, INSERT, UPDATE, or DELETE.

Calculate min distance between points in PostGIS - Geographic Information Systems Stack Exchange

• https://gis.stackexchange.com/questions/52792/calculate-min-distance-between-points-in-postgis

ST_Distance

• http://postgis.net/docs/manual-2.4/ST_Distance.html

• ST_Distance — For geometry type Returns the 2D Cartesian distance between two geometries in projected units (based on spatial ref). For geography type defaults to return minimum geodesic distance between two geographies in meters.

Boundless : Introduction to PostGIS : 27. Nearest-Neighbour Searching

• http://workshops.boundlessgeo.com/postgis-intro/knn.html

Boundless : Introduction to PostGIS : 29. Advanced Geometry Constructions

• http://workshops.boundlessgeo.com/postgis-intro/advanced_geometry_construction.html

學習筆記之Nearest-Neighbour Searching with PostGIS