题解 | SQL必知必会 SQL95
从 Products 表中检索所有的产品名称以及对应的销售总数
https://www.nowcoder.com/practice/2b289b78de1546f38fd24e17e56f1bec
select prod_name, (select sum(quantity) from OrderItems where OrderItems.prod_id = Products.prod_id ) as quant_sold from Products