描述

返回二维或三维边界框或几何图形的X最小值。

	虽然该函数仅为box3d定义，但由于自动强制转换，它也适用于box2d和几何值。但是，它不会接受几何体或box2D文本表示，因为它们不会自动转换。

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

示例

SELECT ST_XMin('BOX3D(1 2 3, 4 5 6)');
st_xmin
-------
1

SELECT ST_XMin(ST_GeomFromText('LINESTRING(1 3 4, 5 6 7)'));
st_xmin
-------
1

SELECT ST_XMin(CAST('BOX(-3 2, 3 4)' As box2d));
st_xmin
-------
-3
--Observe THIS DOES NOT WORK because it will try to auto-cast the string representation to a BOX3D
SELECT ST_XMin('LINESTRING(1 3, 5 6)');

--ERROR:  BOX3D parser - doesn't start with BOX3D(

SELECT ST_XMin(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)'));
st_xmin
--------
220186.995121892
                

另请参阅

ST_XMax, ST_YMax, ST_YMin, ST_ZMax, ST_ZMin