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

Which shipping agent shipped the most documents? List the shipping agent name and the number of documents.
SELECT Ref_Shipping_Agents.shipping_agent_name, COUNT(Documents.document_id) FROM Ref_Shipping_Agents JOIN Documents ON Documents.shipping_agent_code = Ref_Shipping_Agents.shipping_agent_code GROUP BY Ref_Shipping_Agents.shipping_agent_code ORDER BY COUNT(Documents.document_id) DESC LIMIT 1
SELECT "Ref_Shipping_Agents"."shipping_agent_name", COUNT("Documents"."document_id") FROM "Ref_Shipping_Agents" JOIN "Documents" ON "Documents"."shipping_agent_code" = "Ref_Shipping_Agents"."shipping_agent_code" GROUP BY "Ref_Shipping_Agents"."shipping_agent_code" ORDER BY COUNT("Documents"."document_id") DESC NULLS LAST LIMIT 1