Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE document_sections (document_name VARCHAR, document_code VARCHAR); CREATE TABLE documents (document_name VARCHAR, document_code VARCHAR)
### Question:
Find all the name of documents without any sections.
### Answer:
SELECT document_name FROM documents WHERE NOT document_code IN (SELECT document_code FROM document_sections)