【简答题】阐述这条查询语句的含义是什么? select cust_name, cust_contact from customers where cust_id in ( select cust_id from orders where order_num in (select order_num from orderitems where prod_id = 'TNT2'))
【简答题】补全语句 Select vend_id,count(*) as num_prods from products group by ________; Select vend_id,count(*) from products where prod_price>=10 group by vend_id ________ count(*)>2;