如何将表中的每一行与所有行进行比较？

Posted 2023-03-24

【中文标题】如何将表中的每一行与所有行进行比较？

【英文标题】：How to compare each row from table with all rows?

【发布时间】：2013-06-12 11:22:06

【问题描述】：

我正在使用 mysql。

将每一行与该表中的所有左侧行进行比较，然后选择 ID 和时间戳，其中 HEADING 介于 -15

myTable
id
heading (In degrees)
timestamp (in seconds)

例如。第一个表行数：

1 - 50 - 133324565
2 - 12 - 133324565
3 - 10 - 133324565
5 - 220 - 133324565
6 - 35 - 133324565
10 - 10 - 133324565
11 - 15 - 133324565
12 - 22 - 133324565
16 - 168 - 133324565

如您所见，ID 不是连续的，所以我不能这样做吗？

SELECT T1.id,T1.heading,T2.id,T2.heading
FROM mytable as T1, mytable as T2
WHERE T1.id > T2.id -1
AND (T1.timestamp > T2.timestamp -10 OR T1.timestamp < T2.timestamp +10)
AND (T1.heading > T2.heading -15 OR T1.heading < T2.heading +15)

【参考方案1】：

SELECT T1.id,T1.heading,T2.id,T2.heading
FROM mytable as T1, mytable as T2
WHERE T1.id > T2.id AND NOT EXISTS (SELECT T3.id FROM mytable as T3 WHERE T3.id<T1.id AND T3.id>T2.id)
AND (T1.timestamp > T2.timestamp -10 OR T1.timestamp < T2.timestamp +10)
AND (T1.heading > T2.heading -15 OR T1.heading < T2.heading +15)