ST_X()

All functions > GEOSPATIAL > ST_X()

Returns the X coordinate of a point (or longitude for geography).

Signatures

X coordinate

Returns: X coordinate (or longitude)

ST_X(point: T) → DOUBLE

With:

• T : Custom types: GEOM_POINT | GEOG_POINT

Signature notes:

• Input must be a Point; other sub kinds return NULL
• On GEOGRAPHY, returns the longitude in degrees (first argument to ST_GEOGPOINT)
• GEOG_POINT uses X = longitude, Y = latitude; mixing lat/long when calling constructors breaks ST_X / ST_Y results
• Returns NULL if the input is NULL

Examples

SELECT
    f1 := ST_X(ST_GEOMPOINT(3.0, 4.0)), -- X of a geometry point
    f2 := ST_X(ST_GEOGPOINT(-122.4194, 37.7749)) -- Longitude of a geography point
;