Assuming you have no other duplicates, you can use: select t.* from t where t.from_city < t.to_city or not exists (select 1 from t t2 where ... ... <看更多>
The DISTINCT keyword in SQL allows you to eliminate duplicate records from the results of your SELECT query. This video explains how to use ... ... <看更多>
i did my research but i find long sql statements that i dont understand if that could help is a simple error. This is the query: -- 3. Write a ... ... <看更多>
