Find Nearest Latitude/Longitude with an SQL Query

On Precision and Data Types

Precision is key in geometric operations. For latitude use DECIMAL(10,8) and DECIMAL(11,8) for longitude. Be wary of performance hits from inefficient queries; large datasets can be sensitive. A separate stored procedure can be beneficial for regular distance verifications, paired with a distance bounding condition to nimbly filter results.

Managing Big Data Efficiently

With big datasets, fine-tuning is vital. Use a bounding box strategy to limit potential points before hammering exact distances. Apply a limit like the closest 100 points, to prevent data overload:

SELECT * FROM (
  SELECT id, lat, long, distance
  FROM (
    SELECT id, lat, long, 
      (your distance calculation here) AS distance 
    FROM locations
    WHERE lat BETWEEN ? AND ? 
      AND long BETWEEN ? AND ?
    -- "In space, no one can hear you scream (without these bounds)" 😉
  ) AS subquery
  ORDER BY distance
  LIMIT 100
  -- "Because more than 100 is just showing off" 😄
) AS limited
ORDER BY distance;


Replace the ? placeholders with max and min latitude/longitude boundaries.

Utilizing Alternate Formulas & Functions

For higher precision needs, use the Vincenty formula. In MySQL 5.7.6 and ahead, leverage ST_Distance_Sphere() to make codes more readable and calculations simple. Experiment and adopt based on precision needs vs. performance metrics.

An Example with PHP

Here's a PHP script example. Here $lat and $long represent your coordinates:

$query = "SELECT id, (6371 * acos(cos(radians($lat)) * cos(radians(lat)) * cos(radians(long) - radians($long)) + sin(radians($lat)) * sin(radians(lat)))) AS distance FROM locations ORDER BY distance LIMIT 1;";
// Execute the query, process results, and securely manage connections... 


MySQL's Spatial Functions

Diving into MySQL's spatial functions, functions like ST_Contains() or ST_Distance() make geo-database interaction more intuitive, offering powerful ways to approach geographic data in SQL.

Pertaining to Security and Maintenance

Always remember to guard against SQL injection risks. Go for parameter binding and sanitize user input. Keep SQL indices updated for smooth database performance.