backend specific

sql/geoname.mysql.sql

@@ -0,0 +1,21 @@
+DROP FUNCTION IF EXISTS fn_distance_cosine_km;
+DELIMITER |
+CREATE FUNCTION fn_distance_cosine (
+    point1 POINT,
+    point2 POINT
+)
+RETURNS DOUBLE
+BEGIN
+    DECLARE latitude_1, longitude_1, latitude_2, longitude_2 DOUBLE;
+    SET latitude_1:=X(point1);
+    SET longitude_1:=Y(point1);
+    SET latitude_2:=X(point2);
+    SET longitude_2:=Y(point2);
+    RETURN ACOS(
+          SIN(RADIANS(latitude_1)) * SIN(RADIANS(latitude_2))
+          + COS(RADIANS(latitude_1)) * COS(RADIANS(latitude_2))
+          * COS(RADIANS(longitude_2 - longitude_1))
+        ) * 6371;
+END
+|
+DELIMITER ;