Question

我知道如何从最近的区域获取物体：

db.execSQL("CREATE TABLE Task ("
                + "id smallint(6) NOT NULL,"
                + "project_id smallint(6) NOT NULL," 
                + "add_date varchar(15) NOT NULL,"
                + "geo_lat double NOT NULL,"
                + "geo_long double NOT NULL,"
                + "additional_info TEXT NULL" + ");");

和

"SELECT * FROM Task WHERE (geo_lat BETWEEN " + lat_bot + " AND " + lat_top + ") AND (geo_long" + " BETWEEN " + long_bot + " AND " + long_top + ")"

但我的问题是如何按最接近的顺序排序？

Answer 1

您应该按照您所在地区的DISTANCE对物体进行排序。以下公式非常复杂，可以构建在Application layer上，而不是sql。

供您参考。使用'hasrsine'公式计算两点之间的大圆距离：

Haversine:   a = sin²(Δφ/2) + cos φ1 ⋅ cos φ2 ⋅ sin²(Δλ/2)
formula:     c = 2 ⋅ atan2( √a, √(1−a) )
             d = R ⋅ c

其中φ是纬度，λ是经度，R是地球半径（平均半径= 6,371km）; 请注意，角度需要以弧度为单位才能传递给trig函数！

参考：Calculate distance, bearing and more between Latitude/Longitude points

如何查询geo Lat / Long并按最近的顺序排序

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