SQLmap Alias for Column in PostgreSQL Web Application

The user describes a web application that executes user-provided SQL queries (PostgreSQL) and returns results to the frontend. They want to use SQLmap to extract data from a single column, but the column must be aliased as "cookie" in the query. The query is sent via a POST request in a JSON body (e.g., {"query":"SELECT datname as cookie FROM pg_database"}). Despite adjusting SQLmap’s --level and --risk parameters, the tool fails to detect vulnerabilities in this setup.