CREATE TABLE Documents (Id VARCHAR)
CREATE TABLE Ref_Shipping_Agents (Id VARCHAR)

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"