How many customers in the building segments have orders with a total price of no less than 50,000?
building segment refers to c_mktsegment = 'BUILDING'; a total price of no less than 50,000 refers to o_totalprice > 50000
SELECT COUNT(T2.c_name) FROM orders AS T1 INNER JOIN customer AS T2 ON T1.o_custkey = T2.c_custkey WHERE T2.c_mktsegment = 'BUILDING' AND T1.o_totalprice > 50000