用mysql选择围绕id的行之前和之后 [英] Select before and after rows around id with mysql

问题描述

我需要使用mySQL获取围绕ID的ID.

I need to get the IDs around an ID with mySQL.

示例:

ID:

2, 4, 5, 9, 11, 15, 19, 22, 25

例如，我需要知道ID 9周围的5个ID. 查询应返回:

I need to know the 5 IDs around the ID 9, for example. The query should return:

4, 5, 9, 11, 15

谢谢！

推荐答案

一种可能的解决方案是

• 计算每个ID减去ID的绝对值.
• 对结果进行排序，并将结果集限制为5条记录.

SQL语句

SELECT ABS(ID - 9), *
FROM   MyTable
ORDER BY
       ABS(ID - 9)
LIMIT  5

编辑 (向ypercube表示此解决方案可能存在的缺陷)

如果要从左侧获取2个id，从右侧获取2个id，则可以按以下方式调整该语句

If the intent is to get 2 id's from the left and two id's from the right, the statement can be adjusted as follows

SELECT * FROM MyTable WHERE ID <= 9 ORDER BY ID DESC LIMIT 3 
UNION ALL
SELECT * FROM MyTable WHERE ID > 9  ORDER BY ID ASC  LIMIT 2

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