如何使用MySQL 8 ST_Distance计算两个坐标（从Google地图）之间的距离？

Question

我的数据库中有一张表格，该表格用于存储Google地图中的位置以及它们返回的坐标。以前，我将lat和lng存储为小数点，并且在将MySQL版本升级到8后，发现存在预定义的数据类型和函数来处理坐标和距离计算。 我创建了如下表，并从Google地图中插入了一些随机值。

CREATE TABLE `Location` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `lat` varchar(50) NOT NULL,
  `lng` varchar(50) NOT NULL,
  `coordinates` point NOT NULL,
  `name` varchar(500) NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `uk_lat_lng` (`lat`,`lng`),
  SPATIAL KEY `sk_coordinates` (`coordinates`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

已插入示例数据

INSERT INTO Location (name, lat, lng, coordinates)
SELECT 'Thayyeni Koomban', '12.33984592973732', '75.41285991668701', POINT(12.33984592973732, 75.41285991668701) UNION
SELECT 'Tejaswini river rafting', '12.29208143873455', '75.4130744934082', POINT(12.29208143873455, 75.4130744934082) UNION
SELECT 'Mossy Forest, Cameron Highlands', '4.5242225', '101.38192709999998', POINT(4.5242225, 101.38192709999998) UNION
SELECT 'Dhanushkodi Point', '9.152226599999999', '79.44291569999996', POINT(9.152226599999999, 79.44291569999996) UNION
SELECT 'KL Sentral', '3.13333', '101.68667000000005', POINT(3.13333, 101.68667000000005) UNION
SELECT 'Kozhippara Waterfalls', '11.3537295', '76.10803290000001', POINT(11.3537295, 76.10803290000001) UNION
SELECT 'Laguna Honda Hospital and Rehabilitation Center', '37.7492806', '-122.45702240000003', POINT(37.7492806, -122.45702240000003) UNION
SELECT 'Singapore Zoo', '1.4043485', '103.79302299999995', POINT(1.4043485, 103.79302299999995) UNION
SELECT 'Taj Mahal', '27.1750151', '78.04215520000002', POINT(27.1750151, 78.04215520000002) UNION
SELECT 'Sea View Point', '11.2643567', '75.76153939999995', POINT(11.2643567, 75.76153939999995) UNION
SELECT 'Club Mahindra Ashtamudi', '8.965749299999997', '76.57136119999996', POINT(8.965749299999997, 76.57136119999996) UNION
SELECT 'Kollam Beach', '8.8756778', '76.58891629999994', POINT(8.8756778, 76.58891629999994) UNION
SELECT 'Tropical Islands', '52.03892399999999', '13.748616999999967', POINT(52.03892399999999, 13.748616999999967) UNION
SELECT 'Taroko National Park', '24.15870679999999', '121.62162969999997', POINT(24.15870679999999, 121.62162969999997) UNION
SELECT 'Lake Tyrrell', '-35.2553505', '142.8419824', POINT(-35.2553505, 142.8419824) UNION
SELECT 'Karthika Regency', '10.0192948', '76.30539509999994', POINT(10.0192948, 76.30539509999994) UNION
SELECT 'Sentosa', '1.2494041', '103.83032090000006', POINT(1.2494041, 103.83032090000006) UNION
SELECT 'Kovalam Beach', '12.7902597', '80.25390390000007', POINT(12.7902597, 80.25390390000007) UNION
SELECT 'Torres del Paine National Park', '-50.9423262', '-73.40678789999998', POINT(-50.9423262, -73.40678789999998) UNION
SELECT 'Niagara Falls', '43.0828162', '-79.07416289999998', POINT(43.0828162, -79.07416289999998);

了解Google坐标使用3857的SRID，因此使用lat和lng的不同组合创建了以下查询以生成点。但是距离似乎都不是准确的。

SELECT 
    name, 
    lat, 
    lng, 
    ST_Distance(ST_SRID(coordinates, 3857), ST_GeomFromText('POINT(10.0120262 76.3586236)', 3857)) AS distance,
    ST_Distance(ST_SRID(POINT(lat, lng), 3857), ST_GeomFromText('POINT(10.0120262 76.3586236)', 3857)) AS lat_lng,
    ST_Distance(ST_SRID(POINT(lng, lat), 3857), ST_GeomFromText('POINT(10.0120262 76.3586236)', 3857)) AS lng_lat_first,
    ST_Distance(ST_SRID(POINT(lng, lat), 3857), ST_GeomFromText('POINT(76.3586236 10.0120262)', 3857)) AS lng_lat_all,
    ST_Distance(ST_SRID(POINT(lng, lat), 3857), ST_SRID(POINT(76.3586236, 10.0120262), 3857)) AS lng_lat_all_x,
    ST_Distance(ST_SRID(POINT(lng, lat), 3857), ST_SRID(POINT(10.0120262, 76.3586236), 3857)) AS lng_lat_all_y, 
    ST_Distance(ST_SRID(POINT(lat, lng), 3857), ST_SRID(POINT(10.0120262, 76.3586236), 3857)) AS lng_lat_all_z   
from test.Location;

我是以正确的方式进行操作还是丢失了某些东西？ 预先感谢。

Answer 1

我不确定。但是ST_Distance接受两个参数。这里是三个参数。示例为

mysql> SET @g1 = Point(1,1);
mysql> SET @g2 = Point(2,2);
mysql> SELECT ST_Distance(@g1, @g2); .