postgres comparing varying character with array from string_to_array - arrays

Question

I'm having problems comparing Postgres types, and would be grateful for some help. I am extracting valid document types from a configuration table that holds a tilda-separated string, as follows:
SELECT string_to_array(value,'|') as document_kinds
FROM company_configs
WHERE option = 'document_kinds'
this gives me an array of values, so
'doc1|doc2|doc3' becomes {doc1,doc2,doc3}
Next I need to select the documents for a given person which match my document types:
SELECT * FROM people
JOIN documents ON ...
WHERE kind IN
(SELECT string_to_array(value,'|') as document_kinds
FROM company_configs
WHERE option = 'document_kinds')
the documents.kind column is 'character varying'
my understanding is that string_to_array is producing an array of text values 'text[]'
This query produces the error 'ERROR: operator does not exist: character varying = text[]'
If I cast 'kind' into text, with
SELECT * FROM people
JOIN documents ON ...
WHERE kind::text IN
(SELECT string_to_array(value,'|') as visa_document_kinds FROM languages_united.company_configs WHERE option = 'visa_document_kinds')
I get the error 'ERROR: operator does not exist: text = text[]'
I'm not sure how to compare the two, and would be grateful for any advice.
Thanks in advance
Dan
Postgres 9.4.1

Answer 1

You can select against any array element by using the ANY operator, if your sub-query returns exactly one row:
SELECT *
FROM people
JOIN documents ON ...
WHERE kind = ANY (
SELECT string_to_array(value,'|') as document_kinds
FROM company_configs
WHERE option = 'document_kinds');
If the sub-query possibly returns multiple rows, you can use the regexp_split_to_table() function:
SELECT *
FROM people
JOIN documents ON ...
JOIN (
SELECT document_kinds
FROM company_configs,
regexp_split_to_table(value, '\|') as document_kinds
WHERE option = 'document_kinds') sub ON sub.document_kinds = kind;
(You will have to tweak this to match the rest of your query.)