Question

我正在试图弄清楚如何从价格＆lt;的表中选择3个相邻的行。当前商品价格。问题是如果我在表中选择第一行，第二行或第三行，我需要选择三个相邻的行围绕当前项目。重点需要放在较低价格的项目上，例如，如果我从表格中选择第三行，我需要选择前两行和第四行。这是我到目前为止的查询：

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：

精选酒店：Americas Best

+---------------+-------+---------+--------+-------+
|  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union两张价格较低且价格较高的记录：

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，您选择3行，在第二个查询中，选择1行（如果存在）。最后，在这些3+1（或3+0）行中，您只选择价格最高的3行。

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小时后，我终于找到了解决方案。我将一个联合与两个选择查询组合在一起，选择3行（包括选定的酒店）和所选酒店后的3行。然后我设置limit 3和order by price asc以及一切它主要起作用。

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：父选择查询中3行的限制仅限制为联合集中的前3行。如何限制在所选酒店之前的2行开始并在联合子集的所选酒店之后的2行结束的偏移量？

如何选择3个相邻的行，并强调MySQL中较低的值？

3 个答案: