3

全部。

我想创建一个 mysql 函数来计算两个地理代码之间的半正弦距离。

 CREATE FUNCTION haversineDistance
                 (
                  lat1 VARCHAR(256), 
                  long1 VARCHAR(256), 
                  lat2 VARCHAR(256), 
                  long2 VARCHAR(256)
                 )
 RETURNS FLOAT DETERMINISTIC
 BEGIN

      DECLARE radLat1 FLOAT;
      DECLARE radLong1 FLOAT;
      DECLARE radLat2 FLOAT;
      DECLARE radLong2 FLOAT;
      DECLARE dLat FLOAT;
      DECLARE dLong FLOAT;
      DECLARE cordLength FLOAT;
      DECLARE centralAngle FLOAT;
      DECLARE distance FLOAT;

      SET radLat1 = CAST(lat1 AS FLOAT) * PI() / 180;
      SET radLong1 = CAST(long1 AS FLOAT) * PI() / 180;
      SET radLat2 = CAST(lat2 AS FLOAT) * PI() / 180;
      SET radLong2 = CAST(long2 AS FLOAT) * PI() / 180;
      SET dLat = radLat2 - radLat1;
      SET dLong = radLong2 - radLong2;
      SET cordLength = POW(SIN(dLat/2),2)+COS(lat1)*COS(lat2)*POW(SIN(dLon/2),2);
      SET centralAngle = 2 * ATAN2(SQRT(cordLength), SQRT(1-cordLength));
      SET distance = 6367 * centralAngle;

      RETURN distance;
 END

但是我遇到了这样的错误;

1064 - 您的 SQL 语法有错误;检查与您的 MySQL 服务器版本相对应的手册,以在第 4 行的 '' 附近使用正确的语法

有人有想法吗?

先感谢您。

4

2 回答 2

2

好的。

解决了。

 DELIMITER $$
 CREATE FUNCTION haversineDistance
                 (
                  lat1 VARCHAR(256), 
                  long1 VARCHAR(256), 
                  lat2 VARCHAR(256), 
                  long2 VARCHAR(256))
 RETURNS FLOAT DETERMINISTIC
 BEGIN

      DECLARE radLat1 FLOAT;
      DECLARE radLong1 FLOAT;
      DECLARE radLat2 FLOAT;
      DECLARE radLong2 FLOAT;
      DECLARE dLat FLOAT;
      DECLARE dLong FLOAT;
      DECLARE cordLength FLOAT;
      DECLARE centralAngle FLOAT;
      DECLARE distance FLOAT;

      SET radLat1 = CAST(lat1 AS DECIMAL(10,10)) * PI() / 180;
      SET radLong1 = CAST(long1 AS DECIMAL(10,10)) * PI() / 180;
      SET radLat2 = CAST(lat2 AS DECIMAL(10,10)) * PI() / 180;
      SET radLong2 = CAST(long2 AS DECIMAL(10,10)) * PI() / 180;
      SET dLat = radLat2 - radLat1;
      SET dLong = radLong2 - radLong2;
      SET cordLength = POW(SIN(dLat/2),2)+COS(lat1)*COS(lat2)*POW(SIN(dLon/2),2);
      SET centralAngle = 2 * ATAN2(SQRT(cordLength), SQRT(1-cordLength));
      SET distance = 6367 * centralAngle;

      RETURN distance;
 END
于 2014-02-14T13:15:13.980 回答
0

现在,由于分号字符在您的函数中作为行分隔符出现,您遇到了错误。

为了进一步解释,直接引用MySQL 文档

默认情况下,mysql 将分号识别为语句分隔符,因此您必须临时重新定义分隔符,以使 mysql 将整个存储程序定义传递给服务器。

这意味着您必须临时覆盖默认分隔符才能编译程序。封装你的程序

DELIMITER $$
   your code for function
$$

然后试一试。

编辑:您可以通过再次指定默认分隔符来更改分隔符

mysql> DELIMITER ;
于 2014-02-12T12:07:46.460 回答