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Suppose that we want to find the five nearest places to (47.470779, -87.890699) using Spherical Law of Cosines, the following MySQL syntax would easily accomplish it:
SELECT * AS place,
(DEGREES(
ACOS(
SIN(RADIANS(47.470779)) * SIN(RADIANS(geo_latitude)) +
COS(RADIANS(47.470779)) * COS(RADIANS(geo_latitude)) *
COS(RADIANS(-87.890699 - geo_longitude))
)
) * 60 * 1.1515)
AS distance FROM `MyDatabase`.`allplaces` ORDER BY distance ASC LIMIT 20 ;
Suppose that we want to find the five nearest places to (47.470779, -87.890699) using Haversine Formula, the following MySQL syntax would easily accomplish it [please refer here to read about the motivation/reasoning behind using atan2() function instead of sin(min()).
SELECT * ,
((2 * 3960 *
ATAN2(
SQRT(
POWER(SIN((RADIANS(47.470779 - geo_latitude))/2), 2) +
COS(RADIANS(geo_latitude)) *
COS(RADIANS(47.470779 )) *
POWER(SIN((RADIANS(-87.890699 - geo_longitude))/2), 2)
),
SQRT(1-(
POWER(SIN((RADIANS(47.470779 - geo_latitude))/2), 2) +
COS(RADIANS(geo_latitude)) *
COS(RADIANS(47.470779 )) *
POWER(SIN((RADIANS(-87.890699 - geo_longitude))/2), 2)
))
)
)) AS distance FROM `MyDatabase`.`allPlaces` ORDER BY distance LIMIT 20;
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