Returns an ST_Geometry value that represents the point set union 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
The type that the ST_Geometry return type represents is one from 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 | R01 | R02 | R03 | R04 | R05 | R06 |
| ST_Point | R01 | R20 | R15 | R22 | R04 | R17 | R19 |
| ST_LineString, GeoSequence | R02 | R15 | R16 | R21 | R15 | R16 | R18 |
| ST_Polygon | R03 | R22 | R21 | R23 | R22 | R21 | R23 |
| ST_MultiPoint | R04 | R04 | R15 | R22 | R04 | R17 | R19 |
| ST_MultiLineString | R05 | R17 | R16 | R21 | R17 | R16 | R18 |
| ST_MultiPolygon | R06 | R19 | R18 | R23 | R19 | R18 | R23 |
Where:
|
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Vantage converts GeoSequence types that are involved in the ST_Union method to ST_LineString values. Therefore, ST_Union never returns a GeoSequence type.