使用SQL地理学获取特定点半径内的位置

Question

我有一个地理类型的SQL表列：

create table dbo.Events
(
  Id int identity not null 
    constraint PK_Events_Id primary key clustered (Id),
  Localization geography not null
);

如何获得半径40公里范围内的所有事件？这可能吗？

谢谢你，米格尔

Answer 1

假设您具有要搜索的点的经度和纬度：

DECLARE @Origin GEOGRAPHY,
        -- distance defined in meters
        @Distance INTEGER = 40000;

-- center point
SET @Origin = GEOGRAPHY::STGeomFromText('POINT(-122.084039 37.42227)', 4326);

-- return all rows from events in 40km radius
SELECT * FROM dbo.Events WHERE @Origin.STDistance(Localizaton) <= @Distance;