Returns an ST_Geometry value that represents the point set difference of two ST_Geometry values.
Valid Data Types
All ST_Geometry types except geometry collections.
This method can be called on 3D geometries (those that include z coordinates). However, the z coordinate is ignored in method calculations. Consequently, any z coordinates returned by this method should be ignored. Teradata recommends using the Make_2D method to strip out the z coordinates of the return value.
Result Type
Returns an ST_Geometry type where the representation is one of the possible set of types in the following table, depending on the parameter types.
| a — b | Ø | ST_Point | ST_LineString, GeoSequence | ST_Polygon | ST_MultiPoint | ST_MultiLineString | ST_MultiPolygon |
|---|---|---|---|---|---|---|---|
| Ø | Ø | Ø | Ø | Ø | Ø | Ø | Ø |
| ST_Point | R01 | R09 | R09 | R09 | R09 | R09 | R09 |
| ST_LineString, GeoSequence | R02 | R02 | R08 | R08 | R02 | R08 | R08 |
| ST_Polygon | R03 | R03 | R03 | R14 | R14 | R14 | R14 |
| ST_MultiPoint | R04 | R13 | R13 | R13 | R13 | R13 | R13 |
| ST_MultiLineString | R05 | R05 | R08 | R08 | R05 | R08 | R08 |
| ST_MultiPolygon | R06 | R06 | R06 | R14 | R06 | R05 | R06 |
Where:
|
|
Vantage converts GeoSequence types that are involved in the ST_Difference method to ST_LineString values. Therefore, ST_Difference never returns a GeoSequence type.