CODEWITHSUNDEEP
sqlsql-servert-sqllatitude-longitude
PeterH
PeterH

Reputation: 1040

Calculate distance between points using Long and Lat in SQL SERVER

I am using the below destination

[BMAnalytics].[dbo].[EUACTIVESTORES]

And it has columns

[Store No]
[Lat]
[Long]

Can I use these columns to self Join the [Store No] so I have each combination of Store to Store listed in two columns, called 'Source' & 'Target'

And then in a third column is it possible to calculate the distance between the two?

I have used the below previously but this only works for one single point to point,

DECLARE @source geography = 'POINT(0 51.5)'
DECLARE @target geography = 'POINT(-3 56)'

SELECT (@source.STDistance(@target))/1000

Ideally, i'd like the distance from each branch to each branch etc.

Any guidance is welcome

Upvotes: 4

Views: 10230

Answers (2)

PeterH
PeterH

Reputation: 1040

FINAL QUERY LOOKS LIKE:

SELECT
      A.[STORE NO] AS 'SOURCE'
      ,B.[STORE NO] AS 'TARGET'
      ,CONVERT(DECIMAL(6,2),(((GEOGRAPHY::Point(A.[Lat], A.[Long], 4326).STDistance(GEOGRAPHY::Point(B.[Lat], B.[Long], 4326)))/1000)/8)*5) AS 'MILES'

FROM
      [bhxsql2014-dev].[BMAnalytics].[dbo].[EUACTIVESTORES] A
JOIN
      [bhxsql2014-dev].[BMAnalytics].[dbo].[EUACTIVESTORES] B on A.[Store No]<>B.[Store No]

WHERE 
         A.LAT        IS NOT NULL
     AND A.[STORE NO] IS NOT NULL
     AND B.LAT        IS NOT NULL
     AND B.[STORE NO] IS NOT NULL

Upvotes: 3

John Cappelletti
John Cappelletti

Reputation: 82010

Here is a quick example using a Self Join

If you can, I would suggest adding a field to your source table which contains the Geography Point, and thus eliminate the need to calculate this value each time you run a query.

Example

Declare @YourTable table ([Store No] int,Lat float,Lng float)
Insert Into @YourTable values
 (1,-8.157908, -34.931675)
,(2,-8.164891, -34.919033)  
,(3,-8.159999, -34.939999)  

Select [From Store] = A.[Store No]
      ,[To Store]   = B.[Store No]
      ,Meters       = GEOGRAPHY::Point(A.[Lat], A.[Lng], 4326).STDistance(GEOGRAPHY::Point(B.[Lat], B.[Lng], 4326))
 From  @YourTable A
 Join @YourTable B on A.[Store No]<>B.[Store No]

Returns

enter image description here

EDIT If you can add a Geography Field

Update YourTable Set GeoPoint = GEOGRAPHY::Point([Lat], [Lng], 4326)

And then the calculation would be 

,Meters = A.GeoPoint.STDistance(B.GeoPoint)

Upvotes: 3

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