SQL Server supports the Open Geospatial Consortium (OGC) methods on geometry instances.
For more information on OGC specifications, see the following:
OGC Specifications, Simple Feature Access Part 1 - Common Architecture
OGC Specifications, Simple Feature Access Part 2 – SQL Options
STArea
STAsBinary
STAsText
STBoundary
STBuffer
STCentroid
STContains
STConvexHull
STCrosses
STCurveN (geometry Data Type)
STCurveToLine (geometry Data Type)
STDifference
STDimension
STDisjoint
STDistance
STEndpoint
STEnvelope
STEquals
STExteriorRing
STGeometryN
STGeometryType
STInteriorRingN
STIntersection
STIntersects
STIsClosed
STIsEmpty
STIsRing
STIsSimple
STIsValid
STLength
STNumCurves (geometry Data Type)
STNumGeometries
STNumInteriorRing
STNumPoints
STOverlaps
STPointN
STPointOnSurface
STRelate
STSrid
STStartPoint
STSymDifference
STTouches
STUnion
STWithin
STX
STY