Question

任何人都可以帮我解决我复杂的SQL请求吗？

我有一个带有产品列表的html页面，以及我想加入过去4个月的装载和销售信息的每个项目。

我想要的结果是： Item1 - Month0（12 in，0 out），Month-1（33 in，36 out）...... Item2 - Month0（10 in，30 out），Month-1（0 in，66 out）......

我的SQL查询：

方法“getProducts”中的产品（简化）：

Select item_id, item_name
From Products

装载

SELECT item_id, CONCAT(YEAR(`load_date`), MONTH(`load_date`)) AS YearMonth,SUM(load_qty) AS total,
            FROM loading
            GROUP BY YearMonth
            WHERE item_id = ?
            ORDER BY YearMonth DESC ', array($productId));

销售

SELECT item_id, CONCAT(YEAR(`load_date`), MONTH(`load_date`)) AS YearMonth,SUM(load_qty) AS total,
            FROM sales
            GROUP BY YearMonth
            WHERE item_id = ?
            ORDER BY YearMonth DESC ', array($productId));

然后我得到PHP文件来调用SQL方法：

$products = $productManager->getProducts();
$this->data['portalProducts'] = $portalProducts;

包含产品清单的最终HTML文件：

<?php foreach ($products as $product): ?>
<table>
    <tr>
        <td><?php echo date("Y - m", strtotime("now"))?></td> //current month
        <td>//here goes current month load</td>
        <td>//here goes current month sale</td>
    </tr>
    <tr>
        <td><?php echo date("Y - m", strtotime("-1 month"))?></td> //last month
        <td>//here goes last month load</td>
        <td>//here goes last month sale</td>
    </tr>
    ..............
</table>

是否可以将上述查询的所有结果合并为一个请求，然后按照我在开头提到的那样显示... 提前谢谢。

Answer 1

您可以按如下方式组合SQL查询：

SELECT p.item_id, p.item_name, cal.year_month, COALESCE( q_in.total, 0 ) AS qty_in, COALESCE( q_out.total, 0 ) AS qty_out
FROM Products AS p
    INNER JOIN
                ( SELECT CONCAT(YEAR(NOW()), MONTH(NOW())) AS `year_month`
                UNION
                SELECT CONCAT(YEAR(NOW() - INTERVAL 1 MONTH), MONTH(NOW() - INTERVAL 1 MONTH)) AS `year_month` ) AS `cal`
            ON 1 = 1
        LEFT JOIN
                    ( SELECT `item_id`, CONCAT(YEAR(`load_date`), MONTH(`load_date`)) AS `year_month`, SUM(`load_qty`) AS `total`,
                    FROM loading
                    WHERE (`load_date` BETWEEN LAST_DAY(NOW() - INTERVAL 2 MONTH) + INTERVAL 1 DAY AND NOW())
                    GROUP BY `item_id`, YEAR(`load_date`), MONTH(`load_date`)) AS q_in
                ON p.item_id = q_in.item_id AND cal.year_month = q_in.year_month
        LEFT JOIN
                    ( SELECT item_id, CONCAT(YEAR(`load_date`), MONTH(`load_date`)) AS `year_month`, SUM(`load_qty`) AS `total`,
                    FROM sales
                    WHERE (`load_date` BETWEEN LAST_DAY(NOW() - INTERVAL 2 MONTH) + INTERVAL 1 DAY AND NOW())
                    GROUP BY `item_id`, YEAR(`load_date`), MONTH(`load_date`)) AS q_out
                ON p.item_id = q_out.item_id AND cal.year_month = q_out.year_month
ORDER BY p.item_id, p.item_name, q_in.year_month

输出示例：

-------------------------------------------------------
| item_id | item_name | year_month | qty_in | qty_out |
-------------------------------------------------------
| 1       | blah      | 201604     | 0      | 16      |
-------------------------------------------------------
| 1       | blah      | 201605     | 12     | 16      |
-------------------------------------------------------

说明：

我使用“日历”子查询生成了一个月份列表，这样即使当某个月的总数量为0和0时，您的输出也总会有当前和前几个月的行：< / p>

( SELECT CONCAT(YEAR(NOW()), MONTH(NOW())) AS YearMonth
                            UNION
                            SELECT CONCAT(YEAR(NOW() - INTERVAL 1 MONTH), MONTH(NOW() - INTERVAL 1 MONTH)) AS YearMonth ) AS Cal

之后我使用左连接加入“loading”和“sales”的查询。

我添加了

WHERE (load_date BETWEEN LAST_DAY(NOW() - INTERVAL 2 MONTH) + INTERVAL 1 DAY AND NOW())

每个子查询将计算限制为仅当前和上个月。这是为了提高性能。

注意：我没有在MySQL中测试查询

产品列表查询中的月度销售额

1 个答案:

说明：