Kategorien:: Geodatenfunktionen

ST_ASEWKB¶

Given a value of type GEOGRAPHY or GEOMETRY, return the binary representation of that value in EWKB (extended well-known binary) format.

Siehe auch:: ST_ASWKB

Syntax¶

ST_ASEWKB( <geography_or_geometry_expression> )

Argumente¶

geography_or_geometry_expression: The argument must be an expression of type GEOGRAPHY or GEOMETRY.

Rückgabewerte¶

Gibt einen Wert vom Typ BINARY zurück.

Nutzungshinweise¶

For GEOGRAPHY objects, the SRID in the return value is always 4326. See the note on EWKT handling.
Verwenden Sie stattdessen ST_ASWKB, um die Ausgabe im WKB-Format zurückzugeben.

Beispiele¶

GEOGRAPHY Examples¶

Das folgende Beispiel veranschaulicht die Funktion ST_ASEWKB: Für die EWKB-Ausgabe wird angenommen, dass der Parameter BINARY_OUTPUT_FORMAT auf HEX (Standardwert des Parameters) gesetzt ist.

create table geospatial_table (id INTEGER, g GEOGRAPHY);
insert into geospatial_table values
    (1, 'POINT(-122.35 37.55)'), (2, 'LINESTRING(-124.20 42.00, -120.01 41.99)');

select st_asewkb(g)
    from geospatial_table
    order by id;
+--------------------------------------------------------------------------------------------+
| ST_ASEWKB(G)                                                                               |
|--------------------------------------------------------------------------------------------|
| 0101000020E61000006666666666965EC06666666666C64240                                         |
| 0102000020E610000002000000CDCCCCCCCC0C5FC00000000000004540713D0AD7A3005EC01F85EB51B8FE4440 |
+--------------------------------------------------------------------------------------------+

GEOMETRY Examples¶

The example below demonstrates how to use the ST_ASEWKB function. The example returns the EWKB representations of two geometries that have different SRIDs.

CREATE OR REPLACE TABLE geometry_table (g GEOMETRY);
INSERT INTO geometry_table VALUES
  ('SRID=4326;POINT(-122.35 37.55)'),
  ('SRID=0;LINESTRING(0.75 0.75, -10 20)');

SELECT ST_ASEWKB(g) FROM geometry_table;

+--------------------------------------------------------------------------------------------+
| ST_ASEWKB(G)                                                                               |
|--------------------------------------------------------------------------------------------|
| 0101000020E61000006666666666965EC06666666666C64240                                         |
| 01020000200000000002000000000000000000E83F000000000000E83F00000000000024C00000000000003440 |
+--------------------------------------------------------------------------------------------+