oracle - 如何找到最近的定位点?
问题描述
我有一张表,其中包含 customer_number、customer_location(lat, long)、current_latched_tower_ID、tower_location(lat,long) 和距离(在 cx 位置和锁定塔位置之间)。我试图找到一个离客户位置非常近的塔,而不是 current_latched_tower。
示例:一位客户当前锁定一个塔(KA001),客户位置与锁定塔位置之间的距离为1.6KM。但是,还有另一个塔(KA002)非常靠近客户位置。因此,其客户位置与最近的塔位置之间的距离为 1.3KM。
桌子
customer_number cx_lat cx_long tower_lat tower_long Latched_tower_ID Distance
34532 6.897257333 79.86474533 6.890487 79.869199 CM0321 0.51477
43445 6.935598403 81.14939421 6.947618 81.160246 BD0010 1.2292
54365 6.866224 79.88215 6.896111 79.868611 CM0037 1.6216
52568 7.113198 80.037247 7.121666 80.028888 GM0121 0.9476
期望输出表
customer_number cx_lat cx_long tower_lat tower_long Latched_tower_ID Distance Cloesed_tower_ID Closed_Distance
34532 6.897257333 79.86474533 6.890487 79.869199 CM0321 0.51477 CM0037 0.43222
52568 7.113198 80.037247 7.121666 80.028888 GM0121 0.9476 NULL NULL
如果没有更近的塔而不是锁定塔“Closed_tower_ID”和“Closed_Distance”列应为 NULL
解决方案
如果您不使用,SDO_GEOM
那么您可以创建 hasrsine 函数来计算两个纬度/经度坐标之间的距离:
CREATE FUNCTION haversine_distance(
lat1 IN NUMBER,
long1 IN NUMBER,
lat2 IN NUMBER,
long2 IN NUMBER
) RETURN NUMBER DETERMINISTIC
IS
PI CONSTANT NUMBER := ASIN(1) * 2;
R CONSTANT NUMBER := 6371000; -- Approx. radius of the earth in m
PHI1 CONSTANT NUMBER := lat1 * PI / 180;
PHI2 CONSTANT NUMBER := lat2 * PI / 180;
DELTA_PHI CONSTANT NUMBER := (lat2 - lat1) * PI / 180;
DELTA_LAMBDA CONSTANT NUMBER := (long2 - long1) * PI / 180;
a NUMBER;
c NUMBER;
BEGIN
a := SIN(delta_phi/2) * SIN(delta_phi/2) + COS(phi1) * COS(phi2) *
SIN(delta_lambda/2) * SIN(delta_lambda/2);
c := 2 * ATAN2(SQRT(a), SQRT(1-a));
RETURN R * c; -- in metres
END;
/
然后,我假设您的数据采用第三范式:
CREATE TABLE towers (
tower_id PRIMARY KEY,
t_lat,
t_long
) AS
SELECT 'CM0321', 6.890487, 79.869199 FROM DUAL UNION ALL
SELECT 'BD0010', 6.947618, 81.160246 FROM DUAL UNION ALL
SELECT 'CM0037', 6.896111, 79.868611 FROM DUAL UNION ALL
SELECT 'GM0121', 7.121666, 80.028888 FROM DUAL;
CREATE TABLE customers (
customer_number PRIMARY KEY,
cx_lat,
cx_long,
latched_tower_id
) AS
SELECT 34532, 6.897257333, 79.86474533, 'CM0321' FROM DUAL UNION ALL
SELECT 43445, 6.935598403, 81.14939421, 'BD0010' FROM DUAL UNION ALL
SELECT 54365, 6.866224000, 79.88215000, 'CM0037' FROM DUAL UNION ALL
SELECT 52568, 7.113198000, 80.03724700, 'GM0121' FROM DUAL;
ALTER TABLE customers ADD CONSTRAINT customers__lti__fk
FOREIGN KEY (latched_tower_id) REFERENCES towers (tower_id);
然后,在 Oracle 12 中,您可以使用以下方法计算更接近的塔:
SELECT c.*,
TO_CHAR(
HAVERSINE_DISTANCE(c.cx_lat, c.cx_long, t.t_lat, t.t_long)/1000,
'FM999990.000'
) AS distance,
ct.tower_id AS closer_tower_id,
TO_CHAR(ct.distance, 'FM999990.000') AS closer_distance
FROM customers c
INNER JOIN towers t
ON (t.tower_id = c.latched_tower_id)
LEFT OUTER JOIN LATERAL(
SELECT ct.*,
HAVERSINE_DISTANCE(
c.cx_lat,
c.cx_long,
ct.t_lat,
ct.t_long
)/1000 AS distance
FROM towers ct
ORDER BY distance ASC
FETCH FIRST ROW ONLY
) ct
ON (ct.tower_id != c.latched_tower_id);
哪个输出:
顾客号码 CX_LAT CX_LONG LATCHED_TOWER_ID 距离 CLOSER_TOWER_ID CLOSER_DISTANCE 43445 6.935598403 81.14939421 BD0010 1.795 54365 6.866224 79.88215 CM0037 3.644 CM0321 3.053 34532 6.897257333 79.86474533 CM0321 0.899 CM0037 0.445 52568 7.113198 80.037247 GM0121 1.318
在 Oracle 12 之前,您可以使用:
SELECT customer_number,
cx_lat,
cx_long,
latched_tower_id,
distance,
CASE
WHEN latched_tower_id != closer_tower_id
THEN closer_tower_id
END AS closer_tower_id,
CASE
WHEN latched_tower_id != closer_tower_id
THEN closer_distance
END AS closer_distance
FROM (
SELECT c.*,
TO_CHAR(
HAVERSINE_DISTANCE(c.cx_lat, c.cx_long, t.t_lat, t.t_long)/1000,
'FM999990.000'
) AS distance,
ct.tower_id AS closer_tower_id,
TO_CHAR(
HAVERSINE_DISTANCE(c.cx_lat, c.cx_long, ct.t_lat, ct.t_long)/1000,
'FM999990.000'
) AS closer_distance,
ROW_NUMBER() OVER (
PARTITION BY c.customer_number
ORDER BY HAVERSINE_DISTANCE(c.cx_lat, c.cx_long, ct.t_lat, ct.t_long)
) AS rn
FROM customers c
INNER JOIN towers t
ON (t.tower_id = c.latched_tower_id)
CROSS JOIN towers ct
ORDER BY
customer_number,
DISTANCE ASC
)
WHERE rn = 1;
db<>在这里摆弄
推荐阅读
- reactjs - 为什么 npm 时刻时区不起作用?(美国/多伦多)
- webpack - webpack 字体真棒,在根目录下转储文件
- html - wordpress 中的谷歌地图 api 显示错误
- firebase - 如何在 Firestore 中获取文档的所有字段?
- javascript - 嵌套中一致的后备加载动画
成分 - javascript - 反应:如果在组件方法中定义,FileReader onloadend 无法识别“this”
- c++ - 如何正确分配动态一维数组作为类的成员?
- laravel - Laravel6中具有多个表关系的搜索结果
- python - 在 Pandas 中,获取 groupby 的大小并将值存储在每一行的新列中
- r - 从数据集中创建 ggplot 函数时出错