Question

我需要比较postgis上的一些空间数据，但我需要与另一个表“card_history”中的几何数据进行比较，包含使用“ST_GeomFromText”函数所需的lat和long字段。但是如何在单个查询中执行此操作？由于我正在研究php（女巫不相关），因此提出大量查询会非常痛苦......

我正在尝试这样的事情：

SELECT ST_Distance_Sphere
  (ST_GeomFromText('POINT(
      (SELECT DISTINCT ON (userid) long from card_history) 
      (SELECT DISTINCT ON (userid) lat from card_history))',4326),
   ST_GeomFromText('POINT(17.0712215 48.15825)',4326)
  )

但是子查询似乎不能作为“POINT”的参数。请帮忙

Answer 1

试试这个

WITH 
lon AS (
    SELECT DISTINCT ON (userid) AS long from card_history
), 

 lat AS (
     SELECT DISTINCT ON (userid) AS lat from card_history
)

SELECT ST_Distance_Sphere(ST_GeomFromText(

'POINT(' || lon.lon || ' ' || lat.lat || ',4326'),

ST_GeomFromText('POINT(17.0712215 48.15825)',4326))

FROM lon, lat;

如何在postgis上使用子查询作为几何参数？

1 个答案: