题解 | #从 Products 表中检索所有的产品名称以及对应的销售总数#

SELECT 
    p.prod_name,
    tb.quantity
FROM (
    SELECT
        prod_id,
        SUM(quantity) quantity
    FROM
        OrderItems
    GROUP BY
        prod_id
    ) tb,
    Products p
WHERE
    tb.prod_id = p.prod_id;