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
https://www.nowcoder.com/practice/a225d8a7bc4f496283fe8e21293e841c
select sum(if (prod_id = "BR01", quantity, 0)) as items_ordered from OrderItems;
使用sum if ,只要prod_id = "BR01"就返回原值,否则返回0
确定已售出产品项 BR01 的总数
https://www.nowcoder.com/practice/a225d8a7bc4f496283fe8e21293e841c
select sum(if (prod_id = "BR01", quantity, 0)) as items_ordered from OrderItems;
使用sum if ,只要prod_id = "BR01"就返回原值,否则返回0
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