ST_ASHEXEWKB

📄字数 762

👁️阅读量 加载中...

功能描述

返回具有 SRID 元数据的几何图形的扩展已知二进制 （EWKB） 表示形式。

语法格式

CLOB ST_ASHEXEWKB(GEOMETRY g1);
CLOB ST_ASHEXEWKB(GEOMETRY g1, VARCHAR NDR_or_XDR);

参数说明

• g1：目标 GEOMETRY 对象。
• NDR_or_XDR：大小端序字符串。NDR: 小端序，XDR：大端序。如果未指定编码，则使用 NDR。

函数返回类型

CLOB 类型

使用说明

1. 此方法支持圆形字符串和曲线。
2. 该函数支持 3d 并且不会丢失 z-index。

示例

SQL> SELECT ST_ASHEXEWKB(ST_GEOMFROMTEXT('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326));

+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|                                                                                               EXPR1                                                                                                |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 0103000020E61000000100000005000000000000000000000000000000000000000000000000000000000000000000F03F000000000000F03F000000000000F03F000000000000F03F000000000000000000000000000000000000000000000000 |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

(1 row)

大端序输出:

SQL> SELECT ST_AsHEXEWKB(ST_GEOMFROMTEXT('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326), 'xdr');

+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|                                                                                               EXPR1                                                                                                |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 0020000003000010E600000001000000050000000000000000000000000000000000000000000000003FF00000000000003FF00000000000003FF00000000000003FF0000000000000000000000000000000000000000000000000000000000000 |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

(1 row)