你可以自己左加入,看看是否有任何匹配
根据最后的OR条件,您可以 Select 在结果集中显示哪些引用
SELECT t1.*
FROM t t1
LEFT JOIN t t2 ON t1.city1 = t2.city2 and t2.city2 = t1.city1 AND t1.dist = t2.dist
WHERE t2.city1 IS NULL
OR t1.city1 > t1.city2
city1 |
city2 |
dist |
Conce |
Santiago |
500 |
New York |
Berlin |
7900 |
Oregon |
Ohio |
5700 |
Rio |
Montreal |
5700 |
Talca |
Linares |
80 |
Tokyo |
Moscow |
4200 |
SELECT 6
SELECT t1.*
FROM t t1
LEFT JOIN t t2 ON t1.city1 = t2.city2 and t2.city2 = t1.city1 AND t1.dist = t2.dist
WHERE t2.city1 IS NULL
OR t2.city1 > t2.city2
city1 |
city2 |
dist |
Berlin |
New York |
7900 |
Conce |
Santiago |
500 |
Montreal |
Rio |
5700 |
Moscow |
Tokyo |
4200 |
Ohio |
Oregon |
5700 |
Talca |
Linares |
80 |
SELECT 6
fiddle个