题解 | 电商平台想要查询出每个商品在 2024 年上半年（1 月至 6 月）的总销售额

select a.product_id, product_name, sum(price*quantity) as total_sales
from products_underline a
join (
    select *
    from sales_underline
    where left(sale_month, 4)=2024 and right(sale_month, 2) in (1, 2, 3, 4, 5, 6)
) b on a.product_id=b.product_id
group by a.product_id, product_name
order by a.product_id