如何匹配对角线上两列(同一张表)的值，不匹配时显示结果

问题描述

我有一个 city 表，它有两列

I have a city table that has two columns

from_city
to_city 

现在假设一行具有以下值

now lets assume that one row has the following values

'lahore'
'peshawar' 

而下一行有

'peshawar'
'lahore'

请注意，这些值是对角匹配的.我想以这种方式显示所有不匹配的行.

Notice that the values match diagonally. I want to display all the rows that don't match in such a manner.

任何帮助将不胜感激.

推荐答案

可能是这样的:

SELECT * 
FROM bus_route b1 
LEFT JOIN bus_route b2 ON b1.from_city=b2.to_city AND b1.to_city=b2.from_city
WHERE b2.from_city IS NULL

这篇关于如何匹配对角线上两列(同一张表)的值，不匹配时显示结果的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！