conversion from nvarchar to numeric fails - sql

Question

I am trying to execute this query but the following error is occurring:
Error converting data type nvarchar to numeric
this is my query :
Select Top 20 *,dbo.GetDistance(35.5,33.8, Longitude, Latitude) as Distance
From ViewBranchCoordinates
order by Distance desc
if i remove this line order by Distance desc the query run normally with no error
this is the function GetDistance
ALTER FUNCTION [dbo].[GetDistance]
(
-- Add the parameters for the function here
#Long decimal(30,24), #Lat decimal(30,24), #Long2 decimal(30,24), #Lat2 decimal(30,24)
)
--decimal(8,6), #Long)
RETURNS decimal(38,28)
AS
BEGIN
-- Declare the return variable here
DECLARE #Distance decimal(38,28)
DECLARE #valueOne decimal(30,24)
DECLARE #valueTwo decimal(30,24)
DECLARE #dLat decimal(30,24)
DECLARE #dLng decimal(30,24)
DECLARE #SectionOne decimal(30,24)
DECLARE #SectionTwo decimal(30,24)
Select #dLat = RADIANS(#Lat - #Lat2)
Select #dLng = RADIANS(#Long - #Long2)
Select #SectionOne = square(sin((#dLat)/2))
Select #SectionTwo = cos(RADIANS(#Lat)) * cos(RADIANS(#Lat2)) * square(sin(#dLng / 2))
Select #valueOne =CONVERT(decimal(30,24),#SectionOne + #SectionTwo)
Select #valueTwo = 2 * ATN2(SQRT(#valueOne), SQRT(1 - #valueOne))
Select #Distance = 6371000 * #valueTwo
RETURN #Distance
END
Any help please

Answer 1

I presume this will fail too?
Select Top 20 *
,dbo.GetDistance(35.5,33.8, cast (Longitude as decimal (30,24)), cast(Latitude as (30,24)) as Distance
From ViewBranchCoordinates
Your function expects data of a certain type. If your lat/long columns are nvarchar then non numeric data can be in those columns.
Search for problem data, e.g.
Select *
From ViewBranchCoordinates
Where try_cast (longitude as numeric) IS NULL
Then you need to fix the data.