Catégories :: Fonctions géospatiales

ST_SRID¶

Returns the SRID (spatial reference system identifier) of a GEOGRAPHY or GEOMETRY object.

Currently, for any value of the GEOGRAPHY type, only SRID 4326 is supported and is returned.

Syntaxe¶

ST_SRID( <geography_or_geometry_expression> )

Arguments¶

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

Renvoie¶

Renvoie une valeur de type NUMBER(4,0).

Notes sur l’utilisation¶

Renvoie NULL si l’entrée est un NULL.

Exemples¶

GEOGRAPHY Examples¶

Cela montre une utilisation simple de la fonction ST_SRID :

SELECT ST_SRID(ST_MAKEPOINT(37.5, 45.5));
+-----------------------------------+
| ST_SRID(ST_MAKEPOINT(37.5, 45.5)) |
|-----------------------------------|
|                              4326 |
+-----------------------------------+

Cela montre l’utilisation de la fonction ST_SRID avec des valeurs NULL :

SELECT ST_SRID(ST_MAKEPOINT(NULL, NULL)), ST_SRID(NULL);
+-----------------------------------+---------------+
| ST_SRID(ST_MAKEPOINT(NULL, NULL)) | ST_SRID(NULL) |
|-----------------------------------+---------------|
|                              NULL |          NULL |
+-----------------------------------+---------------+