Oracle SQL：为每个id显示n行

Question

我有一个包含2列ID和URL的表，每个ID都有几个URL。我想每个ID只提取5个最大URL。我如何在Oracle SQL中执行此操作？

Answer 1

试试这个，

SELECT ID, URL
FROM
    (
        SELECT ID, URL,
               ROW_NUMBER() OVER (PARTITION BY ID ORDER BY URL DESC) RN
        FROM   tableName
    ) a
WHERE RN <= 5

SQLFiddle Demo