问题描述

我不太喜欢数据库，我对实施本教程有以下疑问:https://mariadb.org/jquery-and-gis-distance-in-mariadb/

I am not so into database and I have the following doubt implementing this tutorial: https://mariadb.org/jquery-and-gis-distance-in-mariadb/

所以基本上我的疑问与这个 SQL 语句有关，它创建了一个函数来计算 MariaDB 数据库上两个 点 之间的距离:

So basically my doubt is relate to this SQL statment that create a function to calculate the distance between two point on a MariaDB database:

CREATE FUNCTION earth_circle_distance(point1 point, point2 point) RETURNS double
    DETERMINISTIC
begin
  declare lon1, lon2 double;
  declare lat1, lat2 double;
  declare td double;
  declare d_lat double;
  declare d_lon double;
  declare a, c, R double;

  set lon1 = X(GeomFromText(AsText(point1)));
  set lon2 = X(GeomFromText(AsText(point2)));
  set lat1 = Y(GeomFromText(AsText(point1)));
  set lat2 = Y(GeomFromText(AsText(point2)));

  set d_lat = radians(lat2 - lat1);
  set d_lon = radians(lon2 - lon1);

  set lat1 = radians(lat1);
  set lat2 = radians(lat2);

  set R = 6372.8; -- in kilometers

  set a = sin(d_lat / 2.0) * sin(d_lat / 2.0) + sin(d_lon / 2.0) * sin(d_lon / 2.0) * cos(lat1) * cos(lat2);
  set c = 2 * asin(sqrt(a));

  return R * c;
end

我的问题是执行前面的语句时，我收到以下错误消息:

My problem is that performing the previous statment I obtain the following error message:

Error
----------------------------------------------------
Static analysis:

2 errors were found during analysis.
    1. Unrecognized data type. (near "point" at position 45)
    2. Unrecognized data type. (near "point" at position 59)

SQL query:

CREATE FUNCTION earth_circle_distance(point1 point, point2 point) RETURNS double DETERMINISTIC begin declare lon1, lon2 double 

MySQL said: 

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '' at line 4

PhpMyAdmin 用 2 个红色标记在上一条语句的第一行标记 point 数据类型:

PhpMyAdmin sign with 2 red marker the point data type on the first line of the previous statment:

CREATE FUNCTION earth_circle_distance(point1 point, point2 point) RETURNS double

但我认为这不是真正的问题(我认为这可能是 PhpMyAdmin 不知道的问题)，因为它也将这个 cration 查询标记为红色:

but I don't think that it could be the real problem (I think that maybe is something that PhpMyAdmin don't know) because it mark red also this cration query:

CREATE TABLE gis_point  (g POINT);

但它工作正常，没有错误并正确创建表.

but it works fine, give me no error and correctly create the table.

那么，哪里错了?可能取决于 PhpMyAdmin 还是我缺少什么?这个函数应该存储在哪里?

So, whta is wrong? Could depend by PhpMyAdmin or what am I missing? Where this function should be stored?

推荐答案

更改分隔符.否则函数定义在第一个 ; 处结束，这会使其不完整.

Change the delimiter. Otherwise the function definition ends at the first ; which would make it incomplete.

delimiter ||
CREATE FUNCTION earth_circle_distance(point1 point, point2 point) RETURNS double
    DETERMINISTIC
begin
  declare lon1, lon2 double;
  declare lat1, lat2 double;
  declare td double;
  declare d_lat double;
  declare d_lon double;
  declare a, c, R double;

  set lon1 = X(GeomFromText(AsText(point1)));
  set lon2 = X(GeomFromText(AsText(point2)));
  set lat1 = Y(GeomFromText(AsText(point1)));
  set lat2 = Y(GeomFromText(AsText(point2)));

  set d_lat = radians(lat2 - lat1);
  set d_lon = radians(lon2 - lon1);

  set lat1 = radians(lat1);
  set lat2 = radians(lat2);

  set R = 6372.8; -- in kilometers

  set a = sin(d_lat / 2.0) * sin(d_lat / 2.0) + sin(d_lon / 2.0) * sin(d_lon / 2.0) * cos(lat1) * cos(lat2);
  set c = 2 * asin(sqrt(a));

  return R * c;
end
||

delimiter ;

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