Sql 从Line-Bigquery中提取n个坐标

我想从大查询中的地理对象（一条线）中提取n个坐标（纬度、经度）

有没有办法指定我要获取多少个

st_geogpoint

？（可以大于或小于使用

st_makeline

创建行时使用的

st_geogpoint

）

例如：

LINESTRING(-115.2893119 36.218517, -115.2892195 36.2184946, -115.2879825 36.2184996, -115.2871506 36.2185021, -115.2870766 36.2185255)  

我希望能够从该行中提取n（其中n>=2）

st_geogpoint

。 可能吗

如果n=2，则预期输出

[POINT(-115.2893119 36.218517), POINT(-115.2870766 36.2185255)]

如果n=10，则预期输出

[POINT(-115.2893119 36.218517),
POINT_2,
POINT_3,
POINT_4,
POINT_5,
POINT_6,
POINT_7,
POINT_8,
POINT_9,
POINT(-115.2870766 36.2185255) ]

---

我不能给出第一个和最后一个之间的点的例子，因为我希望它们是根据下面的n

值从行中提取出来的，这是BigQuery标准SQL

#standardSQL
SELECT 
  SAFE.ST_GEOGFROMTEXT(CONCAT('POINT(', point, ')')) geo_object
FROM `project.dataset.table`,
UNNEST(REGEXP_EXTRACT_ALL(ST_ASTEXT(geo_object), r'[^,\(\)]+')) point WITH OFFSET pos
WHERE pos BETWEEN 1 AND 3

您可以使用问题中的样本数据测试、播放上述内容，如下例所示

#standardSQL
WITH `project.dataset.table` AS (
  SELECT ST_GEOGFROMTEXT('LINESTRING(-115.2893119 36.218517, -115.2892195 36.2184946, -115.2879825 36.2184996, -115.2871506 36.2185021, -115.2870766 36.2185255)') geo_object
)
SELECT 
  SAFE.ST_GEOGFROMTEXT(CONCAT('POINT(', point, ')')) geo_object
FROM `project.dataset.table`,
UNNEST(REGEXP_EXTRACT_ALL(ST_ASTEXT(geo_object), r'[^,\(\)]+')) point WITH OFFSET pos
WHERE pos BETWEEN 1 AND 3   

结果

Row geo_object   
1   POINT(-115.2893119 36.218517)    
2   POINT(-115.2892195 36.2184946)   
3   POINT(-115.2879825 36.2184996)     

显然，通过调整下线中的1和3，您可以控制要输出的点数

WHERE pos BETWEEN 1 AND 3   

如果希望输出与数组位于同一行中，请参见下文

#standardSQL
WITH `project.dataset.table` AS (
  SELECT ST_GEOGFROMTEXT('LINESTRING(-115.2893119 36.218517, -115.2892195 36.2184946, -115.2879825 36.2184996, -115.2871506 36.2185021, -115.2870766 36.2185255)') geo_object
)
SELECT 
  ARRAY(
    SELECT SAFE.ST_GEOGFROMTEXT(CONCAT('POINT(', point, ')'))
    FROM UNNEST(REGEXP_EXTRACT_ALL(ST_ASTEXT(geo_object), r'[^,\(\)]+')) point WITH OFFSET pos
    WHERE pos BETWEEN 1 AND 3  
    AND NOT point IS NULL
  ) geo_objects
FROM `project.dataset.table`

这个产生数组

Row geo_objects  
1   POINT(-115.2893119 36.218517)    
    POINT(-115.2892195 36.2184946)   
    POINT(-115.2879825 36.2184996)      

---

下面是BigQuery标准SQL

#standardSQL
SELECT 
  SAFE.ST_GEOGFROMTEXT(CONCAT('POINT(', point, ')')) geo_object
FROM `project.dataset.table`,
UNNEST(REGEXP_EXTRACT_ALL(ST_ASTEXT(geo_object), r'[^,\(\)]+')) point WITH OFFSET pos
WHERE pos BETWEEN 1 AND 3

您可以使用问题中的样本数据测试、播放上述内容，如下例所示

#standardSQL
WITH `project.dataset.table` AS (
  SELECT ST_GEOGFROMTEXT('LINESTRING(-115.2893119 36.218517, -115.2892195 36.2184946, -115.2879825 36.2184996, -115.2871506 36.2185021, -115.2870766 36.2185255)') geo_object
)
SELECT 
  SAFE.ST_GEOGFROMTEXT(CONCAT('POINT(', point, ')')) geo_object
FROM `project.dataset.table`,
UNNEST(REGEXP_EXTRACT_ALL(ST_ASTEXT(geo_object), r'[^,\(\)]+')) point WITH OFFSET pos
WHERE pos BETWEEN 1 AND 3   

结果

Row geo_object   
1   POINT(-115.2893119 36.218517)    
2   POINT(-115.2892195 36.2184946)   
3   POINT(-115.2879825 36.2184996)     

显然，通过调整下线中的1和3，您可以控制要输出的点数

WHERE pos BETWEEN 1 AND 3   

如果希望输出与数组位于同一行中，请参见下文

#standardSQL
WITH `project.dataset.table` AS (
  SELECT ST_GEOGFROMTEXT('LINESTRING(-115.2893119 36.218517, -115.2892195 36.2184946, -115.2879825 36.2184996, -115.2871506 36.2185021, -115.2870766 36.2185255)') geo_object
)
SELECT 
  ARRAY(
    SELECT SAFE.ST_GEOGFROMTEXT(CONCAT('POINT(', point, ')'))
    FROM UNNEST(REGEXP_EXTRACT_ALL(ST_ASTEXT(geo_object), r'[^,\(\)]+')) point WITH OFFSET pos
    WHERE pos BETWEEN 1 AND 3  
    AND NOT point IS NULL
  ) geo_objects
FROM `project.dataset.table`

这个产生数组

Row geo_objects  
1   POINT(-115.2893119 36.218517)    
    POINT(-115.2892195 36.2184946)   
    POINT(-115.2879825 36.2184996)      

---

假设输入是您的文档中已经显示的文本行，您能否澄清您的用例或至少显示您的预期输出question@MikhailBerlyant我已经添加了预期的输出。Thanksit现在很清楚了：o）假设输入是您的文档中已经显示的文本行，您能否澄清您的用例或至少显示您的预期输出question@MikhailBerlyant我已经添加了预期的输出。谢谢，现在一切都清楚了：o）