ST_Y
Description
Returns the Y coordinate of a valid POINT geometry. In geospatial contexts, the Y coordinate typically corresponds to Latitude, ranging from [-90.0, 90.0] (in degrees).
Sytax
ST_Y( <point>)Parameters
| Parameters | Description |
|---|---|
<point> | A valid 2D POINT geometry from which to extract the Y coordinate. The Y value (latitude) must be within [-90.0, 90.0], and the X value (longitude) must be within [-180.0, 180.0]. |
Retuen value
The Y coordinate of the input POINT, returned as a DOUBLE PRECISION FLOAT.
Returns the Y coordinate (latitude) for valid POINT inputs. Returns NULL for NULL inputs, empty points (POINT EMPTY), 3D points, or invalid points (e.g., latitude outside [-90.0, 90.0]).
Examples
Valid Point
SELECT ST_Y(ST_Point(24.7, 56.7));+----------------------------+
| ST_Y(ST_Point(24.7, 56.7)) |
+----------------------------+
| 56.7 |
+----------------------------+Empty Point (POINT EMPTY)
mysql> SELECT ST_Y(ST_GeometryFromText("POINT EMPTY"));
+------------------------------------------+
| ST_Y(ST_GeometryFromText("POINT EMPTY")) |
+------------------------------------------+
| NULL |
+------------------------------------------+3D Point (Not Supported)
mysql> SELECT ST_Y(ST_GeometryFromText("POINT (10 20 30)"));
+-----------------------------------------------+
| ST_Y(ST_GeometryFromText("POINT (10 20 30)")) |
+-----------------------------------------------+
| NULL |
+-----------------------------------------------+NULL Input
mysql> SELECT ST_Y(NULL);
+------------+
| ST_Y(NULL) |
+------------+
| NULL |
+------------+Invalid Latitude (Out of Range)
mysql> SELECT ST_Y(ST_Point(116.4, 91));
+---------------------------+
| ST_Y(ST_Point(116.4, 91)) |
+---------------------------+
| NULL |
+---------------------------+Invalid Longitude (Out of Range)
mysql> SELECT ST_Y(ST_Point(190, 39.9));
+---------------------------+
| ST_Y(ST_Point(190, 39.9)) |
+---------------------------+
| NULL |
+---------------------------+