ST_Distance (Numeric Distance)

Use this skill when you need the numeric distance value between geometries (for reporting, ranking display, metadata).

If you need a boolean “within X distance” filter, prefer ST_DWithin (faster). A common pattern is:

• use ST_DWithin to filter candidates
• use ST_Distance to compute the returned distance value

Core rules

• Units depend on type:
  • geometry → SRID units (degrees/meters/feet depending on SRID)
  • geography → meters
• Geometries must be in the same SRID for geometry math
• Do not compute meaningful distances in EPSG:4326 geometry (degrees) unless you intend degrees

Canonical patterns