I get a query error 'unknown column' while the column exists
You are using aliases for those tables. So, specify the alias when selecting the column.

CREATE VIEW survey_codes_complete_overview AS 
SELECT *, 
a.supplier_id AS a_id, 
b.supplier_id AS b_id 
FROM wp_jpnx_survey_code AS a 
LEFT JOIN wp_jpnx_survey_supplier_info AS b 
ON a.supplier_id = b.supplier_id