Postgresql函数和运算符最多可以包含一个set参数错误

Question

我正在玩PostGIS，我不明白这个请求有什么问题？

WITH ligne AS (SELECT 42 AS id, ST_transform('SRID=4326;LINESTRING(2.232 48.818, 2.246 48.82)'::geometry, 27572) AS geom)
SELECT ST_locate_along_measure(ST_addmeasure(geom, 0, ST_Length(geom)), generate_series(0, ST_length(geom)::int, 50)) FROM ligne;

我收到错误：错误：函数和运算符最多只能占用一个参数

此请求正在运行，但我不明白两者之间的区别：

WITH ligne AS (SELECT 42 AS id, ST_transform('SRID=4326;LINESTRING(2.232 48.818, 2.246 48.82)'::geometry, 27572) AS geom),
ligne3dm AS (SELECT ST_addmeasure(geom, 0, ST_Length(ligne.geom)) as geom FROM ligne),
pas50m AS (SELECT generate_series(0, ST_length(ligne.geom)::int, 50) as pas FROM ligne)
SELECT ROW_NUMBER() OVER () AS id, ST_locate_along_measure(ligne3dm.geom, pas50m.pas) FROM ligne3dm, pas50m;

Answer 1

解决方案很简单，generate_series返回一个生成器，但ST_Locate_Along_Measure正在等待一个整数。

这将有效：

WITH ligne AS (SELECT 42 AS id, ST_transform('SRID=4326;LINESTRING(2.232 48.818, 2.246 48.82)'::geometry, 27572) AS geom),
generator AS (SELECT generate_series(0, ST_Length(ligne.geom)::int, 50) as pas FROM ligne)
SELECT ST_locate_along_measure(ST_addmeasure(ligne.geom, 0, ST_Length(ligne.geom)), generator.pas) FROM ligne, generator;