如何在 SQL Server 2012 中避免或启用分组依据中的地理字段？

Question

如何计算 select 语句中给定点与数据库 users.GeoLocation 之间的距离。我需要 group by 子句（此查询已简化。）。但是 SQL 服务器正在抱怨：

类型"geography"不可比较。不能在GROUP BY子句中使用。

如果我将它从 group by 子句中删除，它也会抱怨。该怎么办？以某种方式转换为另一种字段类型？

SELECT    geography::STGeomFromText('POINT(-122.34900 47.65100)', 4326).STDistance(users.GeoLocation) AS distanceKM,                    
          users.ID
FROM      users_Users AS users
GROUP BY  users.ID,
          users.GeoLocation

Answer 1

您可以只从分组中取出 GeoLocation 列，然后作为单独的（子）查询进行计算。例如：

DECLARE @fixedPoint GEOGRAPHY = geography::STGeomFromText('POINT(-122.34900 47.65100)', 4326);

WITH UserGrouping AS
(
    SELECT
        // Other Columns
        users.ID
    FROM
        users_Users AS users
    GROUP BY
        users.ID
)
SELECT
    UG.*,
    users.GeoLocation.STDistance(@fixedPoint) AS distanceKM
FROM
    UserGrouping AS UG
    JOIN
    users_Users AS users ON (UG.ID = users.ID);

如何在 SQL Server 2012 中避免或启用分组依据中的地理字段？

How to avoid or enable geography field in group by in SQL Server 2012?

group-by

spatial

sql-server-2012