Odległość HAVERSINE w BigQuery?

Question

Szukam sposobu na uzyskanie HAVERSINE() w BigQuery. Na przykład, jak doprowadzić najbliższe stacje meteorologiczne do dowolnego punktu?

Answer 1

Korzystanie standard SQL można zdefiniować funkcję SQL do hermetyzacji logiki. Na przykład,

#standardSQL 
CREATE TEMP FUNCTION RADIANS(x FLOAT64) AS (
    ACOS(-1) * x/180 
); 
CREATE TEMP FUNCTION RADIANS_TO_KM(x FLOAT64) AS (
    111.045 * 180 * x/ACOS(-1) 
); 
CREATE TEMP FUNCTION HAVERSINE(lat1 FLOAT64, long1 FLOAT64, 
           lat2 FLOAT64, long2 FLOAT64) AS (
    RADIANS_TO_KM(
    ACOS(COS(RADIANS(lat1)) * COS(RADIANS(lat2)) * 
     COS(RADIANS(long1) - RADIANS(long2)) + 
     SIN(RADIANS(lat1)) * SIN(RADIANS(lat2)))) 
); 

SELECT 
    lat, 
    lon, 
    name, 
    HAVERSINE(40.73943, -73.99585, lat, lon) AS distance_in_km 
FROM `bigquery-public-data.noaa_gsod.stations` 
WHERE lat IS NOT NULL AND lon IS NOT NULL 
ORDER BY distance_in_km 
LIMIT 4; 

Answer 2

rozwiązanie Legacy SQL (standard Oczekuje):

SELECT lat, lon, name, 
    (111.045 * DEGREES(ACOS(COS(RADIANS(40.73943)) * COS(RADIANS(lat)) * COS(RADIANS(-73.99585) - RADIANS(lon)) + SIN(RADIANS(40.73943)) * SIN(RADIANS(lat))))) AS distance 
FROM [bigquery-public-data:noaa_gsod.stations] 
HAVING distance>0 
ORDER BY distance 
LIMIT 4 

(na podstawie http://www.plumislandmedia.net/mysql/haversine-mysql-nearest-loc/)