SQL

Question

制作经销商定位器，人们可以在其中搜索附近的经销商。我希望它的工作方式是，如果经销商在该人附近有多个分支机构，则仅显示最近的分支机构。因此 "name" 字段在结果中应该是唯一的，与具有相同 "name" 字段的其他行相比，显示的结果与搜索人员的距离最小。我还希望只显示最近的 5 个经销商，按他们的经销商级别或奖牌排序。现在我有以下内容：

$query = sprintf("SELECT
name, address, contact, image, medal, phone, email, website, lat, lng,
( 3959 * acos( cos( radians('%s') ) * cos( radians( lat ) ) * cos( radians( lng ) - radians('%s') ) + sin( radians('%s') ) * sin( radians( lat ) ) ) ) AS distance
FROM dealers
HAVING distance < 60
ORDER BY medal, distance
LIMIT 0 , 5",
mysql_real_escape_string($center_lat),
mysql_real_escape_string($center_lng),
mysql_real_escape_string($center_lat),
mysql_real_escape_string($radius));
$result = mysql_query($query);

从我读到的内容来看，我似乎需要做类似的事情：

SELECT * FROM (
SELECT ROW_NUMBER() OVER (PARTITION BY name ORDER BY distance) AS num
FROM dealers)a
WHERE a.num = 1

或类似的东西，但我无法让它正常工作。非常感谢任何关于如何让它发挥作用的见解。

Answer 1

获取每个经销商的最小距离，其中取前五个。然后从 table 再次 select 以获得完整的记录，但只取那些已经由经销商和距离识别的记录。

WITH 子句会有所帮助，但 MySQL 不支持它。嗯，...

SELECT
  name, address, contact, image, medal, phone, email, website, lat, lng,
  ( 3959 * acos( cos( radians('%s') ) * cos( radians( lat ) ) * cos( radians( lng ) - radians('%s') ) + sin( radians('%s') ) * sin( radians( lat ) ) ) ) AS distance
FROM dealers
WHERE (name, ( 3959 * acos( cos( radians('%s') ) * cos( radians( lat ) ) * cos( radians( lng ) - radians('%s') ) + sin( radians('%s') ) * sin( radians( lat ) ) ) )) IN
(
  SELECT
    name, min( 3959 * acos( cos( radians('%s') ) * cos( radians( lat ) ) * cos( radians( lng ) - radians('%s') ) + sin( radians('%s') ) * sin( radians( lat ) ) ) ) AS distance
  FROM dealers
  GROUP BY name
  HAVING distance < 60
  ORDER BY distance
  LIMIT 5
)
ORDER BY distance, medal;

Answer 2

最终解决方案是：

        SELECT name, address, contact, image, medal, phone, email, website, lat, lng, 
    ( 3959 * acos( cos( radians('%s') ) * cos( radians( lat ) ) * cos( radians( lng ) - radians('%s') ) + sin( radians('%s') ) * sin( radians( lat ) ) ) ) AS distance 
    FROM dealers 
    WHERE (name,
        ( 3959 * acos( cos( radians('%s') ) * cos( radians( lat ) ) * cos( radians( lng ) - radians('%s') ) + sin( radians('%s') ) * sin( radians( lat ) ) ) ) )
        IN 
        (SELECT name, distance 
            FROM (SELECT name,
            MIN( 3959 * acos( cos( radians('%s') ) * cos( radians( lat ) ) * cos( radians( lng ) - radians('%s') ) + sin( radians('%s') ) * sin( radians( lat ) ) ) ) AS distance
            FROM dealers 
            WHERE (3959 * acos( cos( radians('%s') ) * cos( radians( lat ) ) * cos( radians( lng ) - radians('%s') ) + sin( radians('%s') ) * sin( radians( lat ) ) ) ) < 90
            GROUP BY name) 
        t) 

    ORDER BY medal, distance 
    LIMIT 0, 5",

    mysql_real_escape_string($center_lat),
    mysql_real_escape_string($center_lng),
    mysql_real_escape_string($center_lat),
    mysql_real_escape_string($center_lat),
    mysql_real_escape_string($center_lng),
    mysql_real_escape_string($center_lat),
    mysql_real_escape_string($center_lat),
    mysql_real_escape_string($center_lng),
    mysql_real_escape_string($center_lat),
    mysql_real_escape_string($center_lat),
    mysql_real_escape_string($center_lng),
    mysql_real_escape_string($center_lat)

谢谢 Thorsten Kettner，让我走上正轨！

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