Question

我们说我有一个看起来像这样的蜂巢表：

ID    event    order_num
------------------------
A      red         2
A      blue        1
A      yellow      3
B      yellow      2
B      green       1
...

我尝试使用collect_list为每个ID生成事件列表。如下所示：

SELECT ID, 
collect_list(event) as events_list,
FROM table
GROUP BY ID;

但是，在我分组的每个ID中，我需要按order_num排序。所以我的结果表看起来像这样：

ID    events_list
------------------------
A      ["blue","red","yellow"]
B      ["green","red"]

我无法在collect_list（）查询之前通过ID和order_num进行全局排序，因为该表非常庞大。有没有办法按照collect_list中的order_num排序？

谢谢！

Answer 1

所以，我找到了answer here。诀窍是使用带有DISTRIBUTE BY和SORT BY语句的子查询。见下文：

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Answer 2

函数sort_array()应该对collect_list()项

进行排序

select ID, sort_array(collect_list(event)) as events_list,
from table
group by ID;

Answer 3

尝试以下操作：

WITH tmp AS (
  SELECT * FROM data DISTRIBUTE BY ID SORT BY ID, order_num desc
)
SELECT ID, collect_list(event)
FROM tmp
GROUP BY ID

在配置单元中的collect_list（）内排序

3 个答案: