What is the name of the customer who has made the minimum amount of payment in one claim?
SELECT t3.customer_details FROM claim_headers AS t1 JOIN policies AS t2 ON t1.policy_id   =   t2.policy_id JOIN customers AS t3 ON t2.customer_id   =   t3.customer_id WHERE t1.amount_piad   =    ( SELECT min ( amount_piad )  FROM claim_headers ) 
minimum amount of payment in one claim refers to MIN(amount_paid); customer who made the payment refers to joining tables: claim_headers, policies, and customers to find customer_details;