How to store longitude & latitude as a geography in sql server 2014?

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慢半拍i
慢半拍i 2020-12-10 02:16

I have locations in longitude and latitude coordinates. My goal is eventually to be able to select all rows from myTable Where distance is less than 2km.

  1. Ho

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  •  天命终不由人
    2020-12-10 02:56

    How can i use the longitute and latitute to store location within a geography column?(because it's supposed to be only one geographic point not two right? not one for longitute and one for latitute?)

    You can use geography::STPointFromText / geography::Point to store longitude and latitude in a geography datatype.

    SELECT geography::STPointFromText('POINT(' + CAST([Longitude] AS VARCHAR(20)) + ' ' + CAST([Latitude] AS VARCHAR(20)) + ')', 4326)
    

    or

    SELECT geography::Point(Latitude, Longitude , 4326)
    

    Reference Link:

    Update Geography column in table

    Now that I've got the geography points, how can i select all the rows within a specific distance(in my case 2km)?

    You can use STDistance like this.

    DECLARE @g geography;
    DECLARE @h geography;
    SET @g = geography::STGeomFromText('POINT(-122.35900 47.65129)', 4326);
    SET @h = geography::STGeomFromText('POINT(-122.34720 47.65100)', 4326);
    SELECT @g.STDistance(@h);
    

    Reference Link:

    Distance between two points using Geography datatype in sqlserver 2008?

    Insert Query

    DECLARE @GeoTable TABLE 
    (
        id int identity(1,1),
        location geography
    )
    --Using geography::STGeomFromText
    INSERT INTO @GeoTable 
    SELECT geography::STGeomFromText('POINT(-122.35900 47.65129)', 4326)
    
    --Using geography::Point
    INSERT INTO @GeoTable 
    SELECT geography::Point(47.65100,-122.34720, 4326);
    

    Get Distance Query

    DECLARE @DistanceFromPoint geography
    SET @DistanceFromPoint =  geography::STGeomFromText('POINT(-122.34150 47.65234)', 4326);
    
    SELECT id,location.Lat Lat,location.Long Long,location.STDistance(@DistanceFromPoint) Distance
    FROM @GeoTable;
    

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