Hive select 数据到一个结构数组中

Question

我正在尝试在 Hive 中找出一种方法来 select 来自平面源的数据并输出到命名结构的数组中。这是我正在寻找的示例...

示例数据：

house_id,first_name,last_name
1,bob,jones
1,jenny,jones
2,sally,johnson
3,john,smith
3,barb,smith

期望的输出：

1   [{"first_name":"bob","last_name":"jones"},{"first_name":"jenny","last_name":"jones"}]
2   [{"first_name":"sally","last_name":"johnson"}]
3   [{"first_name":"john","last_name":"smith"},{"first_name":"barb","last_name":"smith"}]

我尝试了 collect_list 和 collect_set，但它们只允许原始数据类型。关于我如何在 Hive 中解决这个问题有什么想法吗？

Answer 1

我会使用这个 jar，它是 collect 的更好实现（并且采用复杂的数据类型）。

查询:

add jar /path/to/jar/brickhouse-0.7.1.jar;
create temporary function collect as 'brickhouse.udf.collect.CollectUDAF';

select house_id
  , collect(named_struct("first_name", first_name, "last_name", last_name))
from db.table
group by house_id

输出:

1   [{"first_name":"bob","last_name":"jones"}, {"first_name":"jenny","last_name":"jones"}]
2   [{"first_name":"sally","last_name":"johnson"}]
3   [{"first_name":"john","last_name":"smith"},{"first_name":"barb","last_name":"smith"}]

Answer 2

您也可以使用变通方法

select collect_list(full_name) full_name_list from (
    select 
        concat_ws(',', 
            concat("first_name:",first_name), 
            concat("last_name:",last_name)
            ) full_name, 
        house_id
    from house) a 
group by house_id

Answer 3

您可以使用 pyspark 或 scalaspark 进行尝试。Spark sql 允许原始数据类型和非原始数据类型。即，你可以做 collect_set( named_struct)

Hive select 数据到一个结构数组中

Hive select data into an array of structs

sql

hadoop

hive

apache-pig

hiveql