[英]Converting values from array in PostgreSQL
In my PostgreSQL database I have the following schema: 在我的PostgreSQL数据库中,我具有以下架构:
CREATE TABLE slide_results (
id integer NOT NULL,
tags character varying[] DEFAULT '{}'::character varying[]
);
INSERT INTO slide_results (id, tags)
VALUES (1, '{Food, Housing}');
INSERT INTO slide_results (id, tags)
VALUES (2, '{Security, Transport}');
Now I want to have sql query that will return one additional column, this column name is domain_name
. 现在,我要进行sql查询,该查询将返回另外一列,此列名称为domain_name
。 Value of this column depends on what tags
column have. 该列的值取决于tags
列所具有的内容。 If tags
column have Food
value then domain_name
should be I need food help
, if tags include Transport
then domain_name
will have Transport help needed
. 如果tags
列具有Food
值,则domain_name
应该是I need food help
;如果标签包含Transport
则domain_name
将具有Transport help needed
。 So result of the query should be 所以查询的结果应该是
id | domain_name
1 | I need food help
2 | Transport help needed
How can I do something like this in PostgreSQL? 如何在PostgreSQL中执行类似的操作?
Here is sql fiddle with db schema: 这是带有数据库模式的sql小提琴:
https://www.db-fiddle.com/f/pP7ZfNzVnisSG6xCjejqkY/0 https://www.db-fiddle.com/f/pP7ZfNzVnisSG6xCjejqkY/0
SELECT id,CASE WHEN 'Food' = ANY(tags) THEN 'I need food help'
WHEN 'Transport' = ANY(tags) THEN 'Transport help needed'
END AS domain_name
FROM slide_results;
It seems you need a table to convert tag
to domain_name
, eg 似乎您需要一个表将tag
转换为domain_name
,例如
create table tag_domain(tag text, domain_name text);
insert into tag_domain values
('Food', 'I need food help'),
('Transport', 'Transport help needed');
and use it in this way: 并以这种方式使用它:
select *
from slide_results s
join tag_domain t on t.tag = any(s.tags)
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