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, SUM(IFNULL(o.quantity, 0)) AS quant_sold # 可能存在有些商品没有销售记录的情况 FROM Products AS p LEFT OUTER JOIN OrderItems AS o ON p.prod_id = o.prod_id GROUP BY p.prod_name;
SELECT p.prod_name, SUM(IFNULL(o.quantity, 0)) AS quant_sold # 可能存在有些商品没有销售记录的情况 FROM Products AS p LEFT OUTER JOIN OrderItems AS o ON p.prod_id = o.prod_id GROUP BY p.prod_name;
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