题解 | #确定已售出产品项 BR01 的总数#
确定已售出产品项 BR01 的总数
http://www.nowcoder.com/practice/a225d8a7bc4f496283fe8e21293e841c
select sum(quantity) as items_ordered from OrderItems where prod_id='BR01';
select sum(quantity) as items_odered from OrderItems group by prod_id having prod_id='BR01';
