arrays - 如何在 hive sql 中将数组转换为字符串？

Question

我想在 hive 中将数组转换为字符串。我想在没有 [[""]] 的情况下将 collect_set 数组值转换为字符串.

select actor, collect_set(date) as grpdate from actor_table group by actor;

以便 [["2016-07-01", "2016-07-02"]]会变成 2016-07-01, 2016-07-02

Answer 1

使用 concat_ws(string delimiter, array<string>)连接数组的函数:

select actor, concat_ws(',',collect_set(date)) as grpdate from actor_table group by actor;

如果日期字段不是字符串，则将其转换为字符串:

concat_ws(',',collect_set(cast(date as string)))

如果您已经有一个(int)数组并且不想分解它以将元素类型转换为字符串，请阅读有关替代方法的答案: How to concatenate the elements of int array to string in Hive