Question

Select p.prodCode,
       p.description,
       p.unit,
       SUM(sd.quantity) "Total quantity"
FROM salesDetail sd
RIGHT JOIN product p
    ON p.prodCode = sd.prodCode
GROUP BY p.prodCode
ORDER BY 4 DESC

帮助！我的脚本没有运行。我需要得到每个产品的总数量，但我的团队不起作用。

Answer 1

计算单独子查询中每种产品的数量总和，然后将其连接回原来的product表：

SELECT t1.prodCode,
       t1.description,
       t1.unit,
       t2.total_quantity
FROM product t1
INNER JOIN
(
    SELECT p.prodCode, SUM(sd.quantity) total_quantity
    FROM product p
    LEFT JOIN salesDetail sd
        ON p.prodCode = sd.prodCode
    GROUP BY p.prodCode
) t2
    ON t1.prodCode = t2.prodCode

请注意，我通过切换子查询中连接表的顺序，将RIGHT JOIN替换为LEFT JOIN。

<强>更新

如果您绝对需要使用RIGHT JOIN，那么只需将子查询替换为：

SELECT p.prodCode, SUM(sd.quantity) total_quantity
FROM salesDetail sd
RIGHT JOIN product p
    ON p.prodCode = sd.prodCode
GROUP BY p.prodCode

DB2中的GROUP BY和RIGHT JOINS

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