PostgreSQL / TypeORM: String array type, how to use LIKE in query? - sql

Question

My backend database is PostgreSQL
I have a TypeORM object simplified to:
#Entity()
#Index(['name'], {unique: true}
export class Foo extends BaseEntity
{
#PrimaryGeneratedColumn('uuid')
id: string;
#Column()
name: string;
#Column('varchar', { array: true })
bar: string[];
}
I'm creating an API query handler that can handle searches. I can easily do a LIKE query on the name like this:
let qs = Foo.createQueryBuilder('foo');
qs.andWhere('foo.name ILIKE :name', {
name:'%${name}%'
});
I'd like to also search for e.g. any "bar" LIKE %myqueryterm% but I can't seem to find anything on that.
I see a bunch of docs on how to exactly match a search term in bar, but no soft comparison.
What I essentially want to do is that I have a data set
[
{id: 1, name: 'whatever', bar: ['apple','bananna','yeti','woo']},
{id: 2, name: 'something else', bar: ['red','blue','green', 'boo']},
{id: 3, name: 'i dunno', bar: ['ford','chevy']},
]
and I'd like to let the user to be able to query e.g. "%oo% and return the first 2 records based on bar strings containing that substring.

Answer 1

Postgres provides array functions and operators that you can use to create any complex query.
In your case, a clean way of doing this would be to
Convert the array to a string and then
Perform the LIKE operation on that string
Something like this should work:
.createQueryBuilder('foo')
.where("array_to_string(foo.bar, ',') LIKE :bar", {
bar: '%aa%',
})
.getMany();

Answer 2

I don't know typeorm. but based on https://github.com/typeorm/typeorm/issues/881
The sql query would be like:
WITH cte (
id,
name,
bar
) AS (
VALUES (1, 'whatever', ARRAY['apple', 'bananna', 'yeti', 'woo']),
(2, 'something else', ARRAY['red', 'blue', 'green', 'boo']),
(3, 'i dunno', ARRAY['ford', 'chevy'])
),
cte1 AS (
SELECT
json_agg(row_to_json(cte.*)) AS json_all
FROM
cte
)
SELECT
value
FROM
cte1,
json_array_elements(json_all)
WHERE
value ->> 'bar' ~ 'oo';
Based on the github page, it would be like:
getConnection().query("
with cte(id,name,bar) as (values
(1,'whatever',array ['apple','bananna','yeti','woo'])
,(2,'something else',array ['red','blue','green', 'boo'])
,(3,'i dunno',array ['ford','chevy'])
),cte1 AS
(select json_agg(row_to_json(cte.*)) as json_all from cte)
select value
from cte1,json_array_elements(json_all)
where value->>'bar' ~ #0", ['oo']);
case insensitively match would be value->>'bar' ~* #0"