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我试图弄清楚如何构建一个函数，使用经度和纬度测量从一个位置到另一个位置的距离（以英里为单位）。运行 EXECUTE 时将添加参数。我正在尝试使用“geography::Point()”和“STDistance”而不是浮点数来做到这一点。

IF OBJECT_ID('dbo.udfDistanceMiles') IS NOT NULL
  DROP FUNCTION dbo.udfDistanceMiles
GO
CREATE FUNCTION dbo.udfDistanceMiles 
(
    @long1 geography,
    @long2 geography,
    @lat1 geography,
    @lat2 geography
)
RETURNS geography
AS
BEGIN
    DECLARE @from geography
    DECLARE @to geography
    DECLARE @kilo geography
    DECLARE @miles as geography

    SET @from = geography::Point(@lat1,@long1,4268);
    SET @to = geography::Point(@lat2,@long2,4268);
    SET @kilo = (SELECT @from.STDistance(@to));
        BEGIN
            SET @miles = (@kilo * '.621371');
        END 

    RETURN @miles

END
GO

这是我正在参加的空间数据库课程的作业，但我遇到了一个我无法弄清楚的障碍。我在尝试创建函数时遇到了这种操作数类型冲突：

Msg 206, Level 16, State 2, Procedure udfDistanceMiles, Line 19
Operand type clash: geography is incompatible with float
Msg 206, Level 16, State 2, Procedure udfDistanceMiles, Line 19
Operand type clash: geography is incompatible with float
Msg 206, Level 16, State 2, Procedure udfDistanceMiles, Line 20
Operand type clash: geography is incompatible with float
Msg 206, Level 16, State 2, Procedure udfDistanceMiles, Line 20
Operand type clash: geography is incompatible with float
Msg 206, Level 16, State 2, Procedure udfDistanceMiles, Line 21
Operand type clash: float is incompatible with geography
Msg 403, Level 16, State 1, Procedure udfDistanceMiles, Line 23
Invalid operator for data type. Operator equals multiply, type equals geography.

对新手的任何帮助将不胜感激。

谢谢

约翰

4

2 回答 2

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看起来您的函数的参数输入不正确。也就是说，如果您要传递 lat/long 对，它们是 float 类型，而不是 geography 类型。你也许可以改变这些，让其他一切都解决。

于 2015-02-04T17:03:28.673 回答
0

这是对我有用的完成的函数，以及它的 EXEC，用于测量从犹他州 SLC 到加利福尼亚州洛杉矶的英里数。

ALTER FUNCTION [dbo].[udfDistanceMiles] 
(
    @long1 float,
    @long2 float,
    @lat1 float,
    @lat2 float
)
RETURNS float
AS
BEGIN
    DECLARE @from geography
    DECLARE @to geography
    DECLARE @miles as float

    SET @from = geography::Point(@lat1,@long1,4326);
    SET @to = geography::Point(@lat2,@long2,4326);
    SET @miles = (SELECT ((@from.STDistance(@to) * '.001') * '.621371'));
    --SET @miles = (SELECT (@from.STDistance(@to) * '.621371'));

    RETURN @miles

END

和执行：

USE DBM384;
GO

DECLARE @miles float= NULL;

EXEC @miles = dbo.udfDistanceMiles @lat1= 34, @long1= -118, @lat2= 40.758701, @long2= -111.876183;

PRINT @miles;
于 2015-02-05T20:19:23.257 回答