Can TRIM function in SQL be more precise? - sql

Question

I have an import table that I want to split into other tables. There's a column in the import table which the data of it's fields have this format: ['email', 'phone', 'facebook'].
In order to separate each value on the field (email, phone and facebook in this case) I'm using the function TRIM when I insert into it's corresponding table, like this:
insert into Media (media)
select distinct trim ('{}' from regexp_split_to_table(host_media, ','))
from ImportH;
But the data inserted into the new table looks dirty, for example in row 1 I would have ['email', in row 2: 'phone' and in row 3: 'facebook'].
How can I make it so the data inserts into the table in a clean way, without the '[' and the floating commas?
I'll provide an image of the import table data of this column and what I get when I split it:

Answer 1

You could just change the splitter:
select *
from regexp_split_to_table('[''email'', ''phone'', ''facebook'']', '[^_a-zA-Z]+') s(value)
where value <> '';
The splitters are just whatever characters are NOT valid characters for the strings you want.
Here is a db<>fiddle.

Answer 2

One of the options... Maybe it will be ok for you:
with trimed as
(select substring(host_media from 2 for length(host_media)-2) as clean_col
from ImportH
)
insert into Media (media)
select unnest(string_to_array(clean_col, ','))
from trimed;
Here is a demo
I have understood the "floating commas" term little bit late so I added some changes to my query:
with trimed as
(select replace(substring(host_media from 2 for length(host_media)-2), '''', '') as clean_col
from ImportH
)
insert into Media (media)
select ltrim(unnest(string_to_array(clean_col, ',')))
from trimed;

Answer 3

Here is a different approach which uses json functions.
First create media table;
CREATE TABLE media AS (
WITH my_medias AS (
SELECT
jsonb_array_elements_text(jsonb_agg(DISTINCT medias ORDER BY medias)) media
FROM impor_th, jsonb_array_elements_text(replace(host_media, '''', '"')::jsonb) medias
)
SELECT
row_number() OVER () media_id,
*
FROM my_medias
);
Then create many-to-many relation table;
CREATE TABLE media_host AS (
WITH elements AS (
SELECT
id,
jsonb_array_elements_text(replace(host_media, '''', '"')::jsonb) media
FROM impor_th i
)
SELECT
e.id AS impor_th_id,
m.media_id
FROM elements e
JOIN media m ON m.media = e.media
);