如何从MySQL表中删除以相反顺序存储的重复值？
为了理解这个概念，我们使用表 'Details_city'中的数据，如下所示：
mysql> Select * from details_city; +--------+--------+ | City1 | City2 | +--------+--------+ | Delhi | Nagpur | | Delhi | Mumbai | | Nagpur | Delhi | | Katak | Delhi | | Delhi | Katak | +--------+--------+ 5 rows in set (0.00 sec)
现在，以下查询将从details_city表中删除反向重复值-
mysql> Select a.city1,a.city2 from details_city a WHERE a.city1 <= a.city2; +-------+--------+ | city1 | city2 | +-------+--------+ | Delhi | Nagpur | | Delhi | Mumbai | | Delhi | Katak | +-------+--------+ 3 rows in set (0.06 sec)