Using SELECT Inside INSERT in PostgreSQL

In SQL, you can use a SELECT statement inside an INSERT to insert data dynamically from another table. For example, the following query inserts records into books by selecting values from the authors table:

INSERT INTO books (author_id, distributor_id, is_archived, reference) 
SELECT id, 2, TRUE, token FROM authors WHERE token = '';

This approach is useful when you need to copy or transform data while inserting, avoiding manual entry. It helps streamline database operations and ensures consistency across related tables.