如何快速识别 array-columns 中的不同组合，然后在 sql 中取消嵌套

Question

我有一个名为程序的数据库创建为

    CREATE TABLE programs (
            name varchar(200) NOT NULL,
            role varchar(200) NOT NULL,
            section text[] NOT NULL,
            sub_section text[] NOT NULL,
            title text[] NOT NULL
            );
    INSERT INTO programs (name, role, section, sub_section, title) VALUES 
            ('John','Lead','{"VII","VII","VII"}','{"A","A","C"}','{"STUDY","STUDY","STUDY"}'), 
            ('Olga','Member','{"VII","VII"}','{"A","A"}','{"STUDY","STUDY"}'),
            ('Ben','Co-Lead','{"XI","X"}','{"A","B"}','{"STUDY","TRAVEL"}'),
            ('Ana','Member','{"VII","II","VI"}','{"A","ALL","B"}','{"STUDY","STUDY","TRAVEL"}');

这是 table 的样子

| name | role    | section      | sub_section | title                    |
| ---- | ------- | ------------ | ----------- | ------------------------ |
| John | Lead    | VII,VII,VII  | A,A,C       | STUDY,STUDY,STUDY        |
| Olga | Member  | VII,VII      | A,A         | STUDY,STUDY              |
| Ben  | Co-Lead | XI,X         | A,B         | STUDY,TRAVEL             |
| Ana  | Member  | VII,II,VI    | A,ALL,B     | STUDY,STUDY,TRAVEL       |

我想识别整个部分、sub-section 和标题列的不同组合，以及取消嵌套以将其作为输出

| name  | role    | section.sub_section | title                    |
| ----  | ------- | ------------------- | ------------------------ |
| John  | Lead    | VII.A               | STUDY
| John  | Lead    | VII.C               | STUDY
| Olga  | Member  | VII.A               | STUDY
| Ben   | Co-Lead | XI.A                | STUDY
| Ben   | Co-Lead | X.B                 | TRAVEL
| Ana   | Member  | VII.A               | STUDY
| Ana   | Member  | II.ALL              | STUDY
| Ana   | Member  | VI.B                | TRAVEL

我是 SQL 的新手，我真的很难获得所需的输出。非常感谢您的帮助。

Answer 1

你想要的数据没有显示“组合横跨部分，sub-section，和标题列”，看来你需要根据位置匹配相应的数组，所以你可以unnest并按要区分的字段分组。

假设相应的列包含 varchars 数组（如果不是 - 您将需要使用一些字符串函数来转换它们）：

-- sample data
WITH dataset (name, role, section, sub_section, title) AS (
    VALUES  ('John','Lead',array['VII','VII','VII'],array['A','A','C'],array['STUDY','STUDY','STUDY']), 
            ('Olga','Member',array['VII','VII'],array['A','A'],array['STUDY','STUDY']),
            ('Ben','Co-Lead',array['XI','X'],array['A','B'],array['STUDY','TRAVEL']),
            ('Ana','Member',array['VII','II','VI'],array['A','ALL','B'],array['STUDY','STUDY','TRAVEL'])

) 

--query
select name,
    role,
    sec || '.' || sub_sec "section.sub_section",
    t title
from dataset
    cross join unnest(section, sub_section, title) as t(sec, sub_sec, t)
group by name, role, sec, sub_sec, t
order by name

输出：

name	role	section.sub_section	title
Ana	Member	VII.A	STUDY
Ana	Member	II.ALL	STUDY
Ana	Member	VI.B	TRAVEL
Ben	Co-Lead	XI.A	STUDY
Ben	Co-Lead	X.B	TRAVEL
John	Lead	VII.A	STUDY
John	Lead	VII.C	STUDY
Olga	Member	VII.A	STUDY

如何快速识别 array-columns 中的不同组合，然后在 sql 中取消嵌套

How do I identify distinct combinations across array-columns and then unnest in sql presto

sql

presto