27 lines
843 B
Markdown
27 lines
843 B
Markdown
---
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layout: post
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title: "Haversine in MySQL"
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date: 2013-03-05 12:49:28+00:00
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permalink: /blog/2013/3/5/haversine-in-mysql
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tags: [mysql, development]
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published: true
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author:
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name: Gergely Polonkai
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email: gergely@polonkai.eu
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---
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Just insert it in your database, feed them two Google coordinates, and you get
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the distance in kilometres. If you happen to need it in miles, change the
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constant `12756.200` in the `RETURN` row to `7922.6` instead.
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{% highlight sql %}
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DELIMITER $$
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CREATE FUNCTION `haversine` (lng1 FLOAT, lat1 FLOAT, lng2 FLOAT, lat2 FLOAT)
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RETURNS float NO SQL DETERMINISTIC
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BEGIN
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SET @a = ABS(POWER(SIN(RADIANS(lat1 - lat2)) / 2, 2) + COS(RADIANS(lat1)) * COS(RADIANS(lat2)) * POWER(SIN(RADIANS(lng1 - lng2)) / 2, 2));
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RETURN 12756.200 * ATAN2(SQRT(@a), SQRT(1 - @a));
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END$$
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{% endhighlight %}
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