ST_GEOMFROMTEXT
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功能描述
从 OGC 已知的文本表示（WKT）构造几何对象。
语法格式
sql
GEOMETRY ST_GEOMFROMTEXT(CLOB WKT);
GEOMETRY ST_GEOMFROMTEXT(CLOB WKT, INTEGER srid);参数说明
- WKT：已知文本字符串。
- srid：空间参考系ID。
函数返回类型
GEOMETRY 类型
使用说明
- 如果未指定，则使用 SRID 0。
- 该方法实现了SQL/MM规范。 SQL-MM 3: 5.1.40
- 此方法支持圆形字符串和曲线。
示例
线串：
sql
SQL> SELECT TO_CHAR(ST_ASTEXT(ST_GEOMFROMTEXT('LINESTRING(-71.160281 42.258729,-71.160837 42.259113,-71.161144 42.25932)')));
+---------------------------------------------------------------------------+
| EXPR1 |
+---------------------------------------------------------------------------+
| LINESTRING(-71.160281 42.258729,-71.160837 42.259113,-71.161144 42.25932) |
+---------------------------------------------------------------------------+
SQL> SELECT TO_CHAR(ST_ASEWKT(ST_GEOMFROMTEXT('LINESTRING(-71.160281 42.258729,-71.160837 42.259113,-71.161144 42.25932)',4269)));
+-------------------------------------------------------------------------------------+
| EXPR1 |
+-------------------------------------------------------------------------------------+
| SRID=4269;LINESTRING(-71.160281 42.258729,-71.160837 42.259113,-71.161144 42.25932) |
+-------------------------------------------------------------------------------------+如果未指定，则使用 SRID 0:
sql
SQL> SELECT ST_SRID(ST_GEOMFROMTEXT('LINESTRING(-71.160281 42.258729,-71.160837 42.259113,-71.161144 42.25932)'));
+-------+
| EXPR1 |
+-------+
| 0 |
+-------+多线串：
sql
SQL> SELECT TO_CHAR(ST_ASTEXT(ST_GEOMFROMTEXT('MULTILINESTRING((-71.160281 42.258729,-71.160837 42.259113,-71.161144 42.25932))')));
+----------------------------------------------------------------------------------+
| EXPR1 |
+----------------------------------------------------------------------------------+
| MULTILINESTRING((-71.160281 42.258729,-71.160837 42.259113,-71.161144 42.25932)) |
+----------------------------------------------------------------------------------+点：
sql
SQL> SELECT TO_CHAR(ST_ASTEXT(ST_GEOMFROMTEXT('POINT(-71.064544 42.28787)')));
+----------------------------+
| EXPR1 |
+----------------------------+
| POINT(-71.064544 42.28787) |
+----------------------------+多边形：
sql
SQL> SELECT TO_CHAR(ST_ASTEXT(ST_GeomFromText('POLYGON((-71.1776585052917 42.3902909739571,-71.1776820268866 42.3903701743239,
-71.1776063012595 42.3903825660754,-71.1775826583081 42.3903033653531,-71.1776585052917 42.3902909739571))')));
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| EXPR1 |
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| POLYGON((-71.1776585052917 42.3902909739571,-71.1776820268866 42.3903701743239,-71.1776063012595 42.3903825660754,-71.1775826583081 42.3903033653531,-71.1776585052917 42.3902909739571)) |
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+多多边形：
sql
SQL> SELECT TO_CHAR(ST_ASEWKT(ST_GEOMFROMTEXT('MULTIPOLYGON(((-71.1031880899493 42.3152774590236,
-71.1031627617667 42.3152960829043,-71.102923838298 42.3149156848307,
-71.1023097974109 42.3151969047397,-71.1019285062273 42.3147384934248,
-71.102505233663 42.3144722937587,-71.10277487471 42.3141658254797,
-71.103113945163 42.3142739188902,-71.10324876416 42.31402489987,
-71.1033002961013 42.3140393340215,-71.1033488797549 42.3139495090772,
-71.103396240451 42.3138632439557,-71.1041521907712 42.3141153348029,
-71.1041411411543 42.3141545014533,-71.1041287795912 42.3142114839058,
-71.1041188134329 42.3142693656241,-71.1041112482575 42.3143272556118,
-71.1041072845732 42.3143851580048,-71.1041057218871 42.3144430686681,
-71.1041065602059 42.3145009876017,-71.1041097995362 42.3145589148055,
-71.1041166403905 42.3146168544148,-71.1041258822717 42.3146748022936,
-71.1041375307579 42.3147318674446,-71.1041492906949 42.3147711126569,
-71.1041598612795 42.314808571739,-71.1042515013869 42.3151287620809,
-71.1041173835118 42.3150739481917,-71.1040809891419 42.3151344119048,
-71.1040438678912 42.3151191367447,-71.1040194562988 42.3151832057859,
-71.1038734225584 42.3151140942995,-71.1038446938243 42.3151006300338,
-71.1038315271889 42.315094347535,-71.1037393329282 42.315054824985,
-71.1035447555574 42.3152608696313,-71.1033436658644 42.3151648370544,
-71.1032580383161 42.3152269126061,-71.103223066939 42.3152517403219,
-71.1031880899493 42.3152774590236)),
((-71.1043632495873 42.315113108546,-71.1043583974082 42.3151211109857,
-71.1043443253471 42.3150676015829,-71.1043850704575 42.3150793250568,-71.1043632495873 42.315113108546)))',4326)));
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| EXPR1 |
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| SRID=4326;MULTIPOLYGON(((-71.1031880899493 42.3152774590236,-71.1031627617667 42.3152960829043,-71.102923838298 42.3149156848307,-71.1023097974109 42.3151969047397,-71.1019285062273 42.3147384934248,-71.102505233663 42.3144722937587,-71.10277487471 42.3141658254797,-71.103113945163 42.3142739188902,-71.10324876416 42.31402489987,-71.1033002961013 42.3140393340215,-71.1033488797549 42.3139495090772,-71.103396240451 42.3138632439557,-71.1041521907712 42.3141153348029,-71.1041411411543 42.3141545014533,-71.1041287795912 42.3142114839058,-71.1041188134329 42.3142693656241,-71.1041112482575 42.3143272556118,-71.1041072845732 42.3143851580048,-71.1041057218871 42.3144430686681,-71.1041065602059 42.3145009876017,-71.1041097995362 42.3145589148055,-71.1041166403905 42.3146168544148,-71.1041258822717 42.3146748022936,-71.1041375307579 42.3147318674446,-71.1041492906949 42.3147711126569,-71.1041598612795 42.314808571739,-71.1042515013869 42.3151287620809,-71.1041173835118 42.3150739481917,-71.1040809891419 42.3151344119048,-71.1040438678912 42.3151191367447,-71.1040194562988 42.3151832057859,-71.1038734225584 42.3151140942995,-71.1038446938243 42.3151006300338,-71.1038315271889 42.315094347535,-71.1037393329282 42.315054824985,-71.1035447555574 42.3152608696313,-71.1033436658644 42.3151648370544,-71.1032580383161 42.3152269126061,-71.103223066939 42.3152517403219,-71.1031880899493 42.3152774590236)),((-71.1043632495873 42.315113108546,-71.1043583974082 42.3151211109857,-71.1043443253471 42.3150676015829,-71.1043850704575 42.3150793250568,-71.1043632495873 42.315113108546))) |
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+圆形字符串：
sql
SQL> SELECT TO_CHAR(ST_ASTEXT(ST_GEOMFROMTEXT('CIRCULARSTRING(220268 150415,220227 150505,220227 150406)')));
+-----------------------------------------------------------+
| EXPR1 |
+-----------------------------------------------------------+
| CIRCULARSTRING(220268 150415,220227 150505,220227 150406) |
+-----------------------------------------------------------+空几何集合：
sql
SQL> SELECT TO_CHAR(ST_ASTEXT(ST_GEOMFROMTEXT('GEOMETRYCOLLECTION EMPTY')));
+--------------------------+
| EXPR1 |
+--------------------------+
| GEOMETRYCOLLECTION EMPTY |
+--------------------------+