Restrict to (the complement of) a value or a set of values

atValue(tnpoint,value) → tnpoint
minusValue(tnpoint,value) → tnpoint
atValues(tnpoint,valueset) → tnpoint
minusValues(tnpoint,valueset) → tnpoint

SELECT atValue(tnpoint '[NPoint(2, 0.3)@2001-01-01, NPoint(2, 0.7)@2001-01-03]',
  'NPoint(2, 0.5)');
-- {[NPoint(2,0.5)@2001-01-02]}
SELECT minusValue(tnpoint '[NPoint(2, 0.3)@2001-01-01, NPoint(2, 0.7)@2001-01-03]',
  'NPoint(2, 0.5)');
/* {[NPoint(2,0.3)@2001-01-01, NPoint(2,0.5)@2001-01-02),
   (NPoint(2,0.5)@2001-01-02, NPoint(2,0.7)@2001-01-03]} */

Restrict to (the complement of) a geometry

atGeometry(tnpoint,geometry) → tnpoint
minusGeometry(tnpoint,geometry) → tnpoint

SELECT atGeometry(tnpoint '[NPoint(2, 0.3)@2001-01-01, NPoint(2, 0.7)@2001-01-03]',
  'Polygon((40 40,40 50,50 50,50 40,40 40))');
SELECT minusGeometry(tnpoint '[NPoint(2, 0.3)@2001-01-01, NPoint(2, 0.7)@2001-01-03]',
  'Polygon((40 40,40 50,50 50,50 40,40 40))');
-- {(NPoint(2,0.342593)@2001-01-01 05:06:40.364673, NPoint(2,0.7)@2001-01-03]}