Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE Documents (Id VARCHAR)
TABLE: CREATE TABLE Ref_Shipping_Agents (Id VARCHAR)

### Question ###
What is the name of the shipping agent of the document with id 2?

### Accurate SQL ###

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