甲骨文LISTAGG结果太长

Question

我使用listagg()聚集字符串值

举例来说，有这样的一个表：

Table1 
Name  Rank 
Bob  A 
Bob  B 
Bob  C 
Tom  A 
Tom  C 

SELECT Name,LISTAGG(RANK,';') WITHIN GROUP (ORDER BY RANK) AS COMRANK 
FROM Table1 

，我们得到的结果：

Name COMRANK 
Bob ABC 
Tom AC 

如果COMRANK变得太长会怎么样？在我汇总它们之前，我能找到最佳的xxx吗？

Answer 1

您可以使用窗口函数对行进行排名，并限制您需要的排名。

SELECT Name,LISTAGG(RANK,';') WITHIN GROUP (ORDER BY RANK) AS COMRANK 
FROM (select 
    name, rank, 
    rank() over (partition by name order by rank) rnk 
    from Table1 
) where rnk < 10; --some value 
GROUP BY Name;