SELECT count(*) FROM Ref_Shipping_Agents JOIN Documents ON Documents.shipping_agent_code = Ref_Shipping_Agents.shipping_agent_code WHERE Ref_Shipping_Agents.shipping_agent_name = "USPS";
How many documents were shipped by USPS?
SELECT count ( * ) FROM Ref_Shipping_Agents JOIN Documents ON Documents.shipping_agent_code = Ref_Shipping_Agents.shipping_agent_code WHERE Ref_Shipping_Agents.shipping_agent_name = `` USPS '' ;
select count ( * ) from ref_shipping_agents join documents on documents.shipping_agent_code = ref_shipping_agents.shipping_agent_code where ref_shipping_agents.shipping_agent_name = value
How many documents were shipped by USPS ?