Postgres空间计算

Posted 2021-11-09 再出发

select * from eploygon;

select * from geometry_columns where f_table_name=\'eploygon\';



-------------------------------------------------------------------------------------------------------------------------------------------------------

SELECT ST_GeomFromText(\'polygon ((117.812658 38.926816,117.813196 38.926622,117.812679 38.925415,117.812065 38.925792,117.812658 38.926816))\', 4326 );
 

SELECT
ST_AsText(
    ST_GeomFromText(\'polygon ((117.812658 38.926816,117.813196 38.926622,117.812679 38.925415,117.812065 38.925792,117.812658 38.926816))\', 4326 )
)
 

SELECT gid,geom FROM public.eploygon s where ST_Intersects( ST_GeomFromText(\'polygon ((117.812658 38.926816,117.813196 38.926622,117.812679 38.925415,117.812065 38.925792,117.812658 38.926816))\', 4326 ) , s.geom) ;


SELECT  ST_GeomFromGeoJSON(\'{"type":"LineString","coordinates":[[0,0],[1,1],[1,1],[2,2]]}\'); 



select ST_GeomFromText(ST_AsText(ST_GeomFromGeoJSON(\'{"type":"LineString","coordinates":[[117.8136920928955,38.92978618569792],[117.81523704528809,38.926781511834875],[117.81620264053345,38.92432760043733],[117.81620264053345,38.92247459068792],[117.81620264053345,38.921489637879205],[117.81624555587769,38.92105558653837]]}\')),4326);

-------------------------------------------------------------------------------------------------------------------------------------------------------
--相交切割计算
 SELECT ST_Intersection(  ST_GeomFromText(ST_AsText(ST_GeomFromGeoJSON(\'{"type":"LineString","coordinates":[[117.8136920928955,38.92978618569792],[117.81523704528809,38.926781511834875],[117.81620264053345,38.92432760043733],[117.81620264053345,38.92247459068792],[117.81620264053345,38.921489637879205],[117.81624555587769,38.92105558653837]]}\')),4326) , s.geom) 
  FROM public.eploygon s where ST_Intersects(  ST_GeomFromText(ST_AsText(ST_GeomFromGeoJSON(\'{"type":"LineString","coordinates":[[117.8136920928955,38.92978618569792],[117.81523704528809,38.926781511834875],[117.81620264053345,38.92432760043733],[117.81620264053345,38.92247459068792],[117.81620264053345,38.921489637879205],[117.81624555587769,38.92105558653837]]}\')),4326) , s.geom) ;
    
      SELECT  ST_Intersection(  ST_GeomFromText(ST_AsText(ST_GeomFromGeoJSON(\'{"type":"Polygon","coordinates":[[[117.812658,38.926816],[117.813196,38.926622],[117.812679, 38.925415],[117.812065,38.925792],[117.812658,38.926816]]]}\')),4326) , s.geom)  FROM public.eploygon s where ST_Intersects(  ST_GeomFromText(ST_AsText(ST_GeomFromGeoJSON(\'{"type":"Polygon","coordinates":[[[117.812658,38.926816],[117.813196,38.926622],[117.812679, 38.925415],[117.812065,38.925792],[117.812658,38.926816]]]}\')),4326) , s.geom) ;
        
        
  SELECT  ST_AsText(ST_Intersection(  ST_GeomFromText(ST_AsText(ST_GeomFromGeoJSON(\'{"type":"Point","coordinates":[117.812658,38.926816]}\')),4326) , s.geom)) as a FROM public.eploygon s;

  SELECT  ST_Intersection(  ST_GeomFromText(ST_AsText(ST_GeomFromGeoJSON(\'{"type":"Point","coordinates":[117.812658,38.926816]}\')),4326) , s.geom) FROM public.eploygon s
    where ST_Intersects(  ST_GeomFromText(ST_AsText(ST_GeomFromGeoJSON(\'{"type":"Point","coordinates":[117.812658,38.926816]}\')),4326) , s.geom);


-------------------------------------------------------------------------------------------------------------------------------------------------------
 --相交计算
 SELECT gid,geom FROM public.eploygon s where ST_Intersects(  ST_GeomFromText(ST_AsText(ST_GeomFromGeoJSON(\'{"type":"LineString","coordinates":[[117.8136920928955,38.92978618569792],[117.81523704528809,38.926781511834875],[117.81620264053345,38.92432760043733],[117.81620264053345,38.92247459068792],[117.81620264053345,38.921489637879205],[117.81624555587769,38.92105558653837]]}\')),4326) , s.geom) ;
 
 
  SELECT gid,geom FROM public.eploygon s where ST_Intersects(  ST_GeomFromText(ST_AsText(ST_GeomFromGeoJSON(\'{"type":"Polygon","coordinates":[[[117.812658,38.926816],[117.813196,38.926622],[117.812679, 38.925415],[117.812065,38.925792],[117.812658,38.926816]]]}\')),4326) , s.geom) ;


  SELECT gid,geom FROM public.eploygon s where ST_Intersects(  ST_GeomFromText(ST_AsText(ST_GeomFromGeoJSON(\'{"type":"Point","coordinates":[117.812658,38.926816]}\')),4326) , s.geom)  ;

-------------------------------------------------------------------------------------------------------------------------------------------------------
--相交计算测试输出
 SELECT gid,geom FROM public.eploygon s where ST_Intersects(  ST_GeomFromText(ST_AsText(ST_GeomFromGeoJSON(\'{"type":"LineString","coordinates":[[117.8136920928955,38.92978618569792],[117.81523704528809,38.926781511834875],[117.81620264053345,38.92432760043733],[117.81620264053345,38.92247459068792],[117.81620264053345,38.921489637879205],[117.81624555587769,38.92105558653837]]}\')),4326) , s.geom) 
 union
 select 111111 as gid,ST_GeomFromText(ST_AsText(ST_GeomFromGeoJSON(\'{"type":"LineString","coordinates":[[117.8136920928955,38.92978618569792],[117.81523704528809,38.926781511834875],[117.81620264053345,38.92432760043733],[117.81620264053345,38.92247459068792],[117.81620264053345,38.921489637879205],[117.81624555587769,38.92105558653837]]}\')),4326);  
 
 
  SELECT gid,geom FROM public.eploygon s where ST_Intersects(  ST_GeomFromText(ST_AsText(ST_GeomFromGeoJSON(\'{"type":"Polygon","coordinates":[[[117.812658,38.926816],[117.813196,38.926622],[117.812679, 38.925415],[117.812065,38.925792],[117.812658,38.926816]]]}\')),4326) , s.geom) 
    union
    select 111111 as gid,ST_GeomFromText(ST_AsText(ST_GeomFromGeoJSON(\'{"type":"Polygon","coordinates":[[[117.812658,38.926816],[117.813196,38.926622],[117.812679, 38.925415],[117.812065,38.925792],[117.812658,38.926816]]]}\')),4326) ; 


  SELECT gid,geom FROM public.eploygon s where ST_Intersects(  ST_GeomFromText(ST_AsText(ST_GeomFromGeoJSON(\'{"type":"Point","coordinates":[117.812658,38.926816]}\')),4326) , s.geom) 
    union
    select 111111 as gid,ST_GeomFromText(ST_AsText(ST_GeomFromGeoJSON(\'{"type":"Point","coordinates":[117.812658,38.926816]}\')),4326);

 

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数据库中存储的 postgres 表空间的位置

【中文标题】数据库中存储的 postgres 表空间的位置

【英文标题】：Where in the DB is the Location of a postgres tablespace stored

【发布时间】：2016-02-05 10:32:44

【问题描述】：

我在 redhat 6 上使用 postgres 9.2

这应该很简单，但我在任何地方都找不到。我正在寻找存储 postgres 表空间位置的数据库表和列，我认为它会在 PG_TABLESPACE 中，但是

select * from pg_tablespace

显示...

postgres=# select * from pg_tablespace;
     spcname     | spcowner | spcacl | spcoptions
-----------------+----------+--------+------------
 pg_default      |       10 |        |
 pg_global       |       10 |        |
 C_TBL_DB91SABIR |       10 |        |
(3 rows)

但没有位置，有什么想法保存位置吗？

谢谢

【问题讨论】：

不是确切的答案：SHOW data_directory; 会告诉你当前数据库的位置

嗨@wingedpanther，它显示了 PGDATA 位置，但我正在寻找表空间的目录，我想查询它，以便我可以在表空间被删除时编写删除物理文件夹的脚本丢弃。

试试这个select spcname, pg_tablespace_location(oid) from pg_tablespace;

【参考方案1】：

使用pg_tablespace_location(tablespace_oid)(PostgreSQL 9.2+)获取tablespace所在文件系统中的路径。

您将从pg_tablespace 获得tablespace 中的oid，因此查询应该是

select spcname
      ,pg_tablespace_location(oid) 
from   pg_tablespace;

【参考方案2】：

另一个列出所有表空间的超级简单命令

\db+

这将很快为您提供所有表空间详细信息

【参考方案3】：

使用以下查询获取表空间名称表空间位置。

postgres=# select spcname ,pg_tablespace_location(oid) from pg_tablespace;
  spcname   |    pg_tablespace_location     
------------+-------------------------------
 pg_default | 
 pg_global  | 
 fastspace  | /var/lib/postgresql/data/base
 demotbs    | /var/lib/postgresql/data

【讨论】：

复制已经接受的答案有什么意义？