您如何 select 3 个相邻行强调 MySQL 中较低的值？

Question

我正在尝试弄清楚如何 select 从 table 的 3 个相邻行中获取价格 < 当前商品价格的方法。问题是，如果我 select 在 table 中的第一行、第二行或第三行，我需要 select 三个相邻的行 around 当前项目。需要强调价格较低的商品，例如，如果我 select 从 table 开始第三行，我需要 select 前两行和第四行排。到目前为止，这是我的查询：

SELECT * 
FROM (SELECT * 
      FROM temp_db_cart 
      WHERE airport='$airport' 
        AND people='$people' 
        AND price < '$price' 
      ORDER BY price DESC LIMIT 3
     ) 
ORDER BY price ASC

示例数据：

+---------------+---------+--------+-------+
|  hotel_name   | airport | people | price |
+---------------+---------+--------+-------+
| Days Inn      | MLB     |      1 |   109 |
| Holiday Inn   | MCO     |      2 |   149 |
| Americas Best | MLB     |      2 |   199 |
| Econo Lodge   | SFB     |      1 |   209 |
+---------------+---------+--------+-------+

预期结果：

所选酒店：美洲最佳

+---------------+-------+---------+--------+-------+
|  hotel_name   | order | airport | people | price |
+---------------+-------+---------+--------+-------+
| Days Inn      | 1     | ..      | ..     | ..    |
| Holiday Inn   | 2     | ..      | ..     | ..    |
| Americas Best | Skip  | ..      | ..     | ..    |
| Econo Lodge   | 3     | ..      | ..     | ..    |
+---------------+-------+---------+--------+-------+

PHP/MySQL 组合可用于答案。任何帮助将不胜感激。

Answer 1

您可以union价格较低的两条记录与价格较高的记录：

select * from
(
(SELECT * 
  FROM temp_db_cart 
  WHERE airport='MCO' 
    AND people='3' 
    AND price < '245' 
  ORDER BY price DESC LIMIT 3)
 UNION
(SELECT * 
  FROM temp_db_cart 
  WHERE airport='MCO' 
    AND people='3' 
    AND price > '245' 
  ORDER BY price LIMIT 1)
)
order by price desc limit 3

在第一个查询中，您 select 3 行，在第二个查询中，1 行（如果存在）。最后，在这些 3+1（或 3+0）行中，您 select 只有 3 行的价格最高。

Answer 2

SELECT * 
 FROM (SELECT MIN(price)
  FROM temp_db_cart 
  WHERE airport='$airport' 
    AND people='$people' 

    AND hotel != '$hotel'
  ORDER BY price DESC LIMIT 3
 ) 
ORDER BY price ASC

Answer 3

2个小时后，我终于找到了解决办法。我将联合与两个 select 查询组合在一起，即 selects 前 3 行（包括 selected 酒店）和 selected 酒店后 3 行。然后我设置 limit 3 和 order by price asc 和一切它主要工作。

SELECT * 
FROM   ( 
       ( 
            SELECT   * 
            FROM     temp_db_cart 
            WHERE    price >= {$package['price']} 
            AND      airport = '{$airport['abbr']}' 
            AND      people = '{$travelers['number-of-travelers']}' 
            ORDER BY price ASC limit 3 ) 
UNION 
         ( 
            SELECT   * 
            FROM     temp_db_cart 
            WHERE    price < {$package['price']} 
            AND      airport = '{$airport['abbr']}' 
            AND      people = '{$travelers['number-of-travelers']}' 
            ORDER BY price DESC limit 3 ) ) AS u 
WHERE    hotel_name != '{$package['hotel_name']}' 
ORDER BY price ASC limit 3;

编辑：父select查询中的3行限制只限于联合集中的前3行。我如何限制从 selected 酒店前 2 行开始到联合子集 selected 酒店后 2 行结束的偏移量？

您如何 select 3 个相邻行强调 MySQL 中较低的值？

How do you select 3 adjacent rows with emphasis on the lower values in MySQL?

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