ST_MinZ

定义

ST_MinZ 以几何对象为输入参数，返回其最小 z 坐标。

语法

sde.st_minz (g1 sde.st_geometry)

返回类型

数值

如果 z 值不存在，则返回 NULL。

示例

Oracle

CREATE TABLE minz_test (id integer, geometry sde.st_geometry);

INSERT INTO MINZ_TEST VALUES (
1901,
sde.st_polygon ('polygon zm((110 120 20 3, 110 140 22 3, 120 130 26 4, 110 120 20 3))', 0)
);

INSERT INTO MINZ_TEST VALUES (
1902,
sde.st_polygon ('polygon zm((0 0 40 7, 0 4 35 9, 5 4 32 12, 5 0 31 5, 0 0 40 7))', 0)
);

SELECT id, sde.st_minz (geometry) MinZ
FROM MINZ_TEST;

        ID       MINZ

      1901         20
      1902         31

PostgreSQL

CREATE TABLE minz_test (id integer, geometry st_geometry);

INSERT INTO minz_test VALUES (
1901,
st_polygon ('polygon zm((110 120 20 3, 110 140 22 3, 120 130 26 4, 110 120 20 3))', 0)
);

INSERT INTO minz_test VALUES (
1902,
st_polygon ('polygon zm((0 0 40 7, 0 4 35 9, 5 4 32 12, 5 0 31 5, 0 0 40 7))', 0)
);

SELECT id, st_minz (geometry) 
AS MinZ
FROM minz_test;

        id       minz

      1901         20
      1902         31