Here are a few title options, varying in style and focus: **Direct & Informative:** * **How to Find Locations Within a Radius Using MySQL: An Improved Query** * **Accurate Geolocation Search in

MySQL Query for Finding Locations Within a Radius

Queries that search for locations within a specified radius are used when dealing with geospatial data. In this case, a query is needed to retrieve all rows within a 25-mile radius of a given latitude and longitude. However, the original query was not returning accurate results for all rows.

Improved Query

The improved query eliminates the incorrect results by using a more accurate formula to calculate the distance between rows:

SELECT
    `id`,
    (
        6371 *
        acos(
            cos( radians( :lat ) ) *
            cos( radians( `lat` ) ) *
            cos(
                radians( `long` ) - radians( :long )
            ) +
            sin(radians(:lat)) *
            sin(radians(`lat`))
        )
    ) `distance`
FROM
    `location`
HAVING
    `distance` < :distance
ORDER BY
    `distance`
LIMIT
    25

Explanation

• The formula acos( ... ) calculates the angle between two latitude-longitude points.
• Multiplying this angle by 6371 converts the result to miles.
• The resulting distance is stored in the distance column.
• All rows with a distance less than the specified value are selected.

Parameters

• :lat and :long are the latitude and longitude of the center point.
• :distance is the desired radius in miles.

Using this improved query, all rows within a specified radius can be accurately retrieved, eliminating the incorrect results seen in the original query.

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