What is the name of the customer whose order was delivered the longest?
name of the customer refers to c_name; delivered the longest refers to max(subtract(l_receiptdate, l_commitdate))
SELECT T3.c_name FROM orders AS T1 INNER JOIN lineitem AS T2 ON T1.o_orderkey = T2.l_orderkey INNER JOIN customer AS T3 ON T1.o_custkey = T3.c_custkey ORDER BY (JULIANDAY(T2.l_receiptdate) - JULIANDAY(T2.l_commitdate)) DESC LIMIT 1