CREATE TABLE document_drafts (document_id NUMBER, draft_number NUMBER, draft_details CLOB)
CREATE TABLE documents_mailed (document_id NUMBER, mailed_to_address_id NUMBER, mailing_date TIME)
CREATE TABLE addresses (address_id NUMBER, address_details CLOB)
CREATE TABLE circulation_history (document_id NUMBER, draft_number NUMBER, copy_number NUMBER, employee_id NUMBER)
CREATE TABLE documents (document_id NUMBER, document_status_code CLOB, document_type_code CLOB, shipping_agent_code CLOB, receipt_date TIME, receipt_number CLOB, other_details CLOB)
CREATE TABLE ref_shipping_agents (shipping_agent_code CLOB, shipping_agent_name CLOB, shipping_agent_description CLOB)
CREATE TABLE ref_document_status (document_status_code CLOB, document_status_description CLOB)
CREATE TABLE roles (role_code CLOB, role_description CLOB)
CREATE TABLE ref_document_types (document_type_code CLOB, document_type_description CLOB)
CREATE TABLE draft_copies (document_id NUMBER, draft_number NUMBER, copy_number NUMBER)
CREATE TABLE employees (employee_id NUMBER, role_code CLOB, employee_name CLOB, other_details CLOB)

What is the name of the shipping agent of the document with id 2?
SELECT ref_shipping_agents.shipping_agent_name FROM ref_shipping_agents JOIN documents ON documents.shipping_agent_code = ref_shipping_agents.shipping_agent_code WHERE documents.document_id = 2
SELECT "ref_shipping_agents"."shipping_agent_name" FROM "ref_shipping_agents" JOIN "documents" ON "documents"."document_id" = 2 AND "documents"."shipping_agent_code" = "ref_shipping_agents"."shipping_agent_code"