如何从两个蜂巢数组中获取不匹配的元素

Posted 2023-03-23

【中文标题】如何从两个蜂巢数组中获取不匹配的元素

【英文标题】：How to get unmatched elements from two hive arrays

【发布时间】：2021-03-31 02:16:31

【问题描述】：

我正在寻找一个 hive 函数和查询以从 Hive 中的两个数组中获取不匹配的元素。假设数组是

A = ["Hello", "earth"]
B = ["Hello", "mars"]
Expected output is ["earth", "mars"] or ["mars", "earth"]

另一个例子

A = ["Hello", "world"]
B = ["Hello", "world", "!"]
Expected output is ["!"]

【参考方案1】：

在子查询中分解两个数组，FULL JOIN子查询并过滤不匹配的记录，然后使用collect_set聚合它们得到数组。

演示：

with your_data as (
select array ("Hello", "earth") A,
array("Hello", "mars") B
)

select collect_set(coalesce(A.element_A,B.element_B)) as result
from
(select element_A 
 from your_data d lateral view explode(A) e as element_A
)A

FULL JOIN 

(select element_B 
 from your_data d lateral view explode(B) e as element_B
)B 
ON A.element_A=B.element_B

WHERE A.element_A is NULL OR B.element_B is NULL

结果：

["earth","mars"]