SQL DISTINCT [替代使用]

Question

我对Oracle有一个简单的查询。

SELECT DISTINCT City, Name, Surname FROM Persons

对于没有DISTINCT的同一查询，是否有任何替代sql查询？

Answer 1

查看this article

示例为;

select City
from (
  select City,
         row_number() over 
           (partition by City
            order by City) rownumber
    from Persons
         ) t
   where rownumber = 1

Answer 2

SELECT City, Name, Surname FROM Persons
UNION
SELECT City, Name, Surname FROM Persons

Answer 3

SELECT First(City), First(Name), First(Surname)
FROM Persons
GROUP BY City, Name, Surname