在连接查询中选择 DISTINCT 行的 SUM

Question

我有两个表，orders 和 orderitems。我正在按日期制作销售报告，其中需要包括每个订单项在每个日期的总成本价格和销售价格以及每个订单在每个日期的总交付成本：

表格：订单

orderid    date          deliverycost
1          2000-01-01    5
2          2000-01-01    3
3          2000-01-02    0
4          2000-01-02    4

表：订单项

orderitemdid    orderid    costprice    sellingprice
1               1          10           12
2               1          2            4
3               2          10           12
4               3          5            6
5               3          4            10
6               4          1            2

我正在寻找将提供以下输出的查询：

date          costprice   sellingprice   deliverycost
2000-01-01    22          28             8    
2000-01-02    10          18             4

我已经尝试了以下 SQL：

        SELECT
            SUM(`orderitem`.`costprice`) AS `costprice`,
            SUM(`orderitem`.`sellingprice`) AS `sellingprice`,
            SUM(`order`.`delivery`) AS `delivery`,
            DATE(`order`.`date`) AS `date`,
        FROM
            `order`
        INNER JOIN
            `orderitem`
        ON
            (`order`.`orderid` = `orderitem`.`orderid`)
        GROUP BY
            `date`
        ORDER BY
            `date`

问题是我最终得到的是交货价格乘以订单商品的数量，所以我希望在加入之前对order.delivery 执行 SUM()。

Answer 1

可能与引号使用不当有关 不要对列名使用单引号，但在需要时使用反引号

   SELECT
        SUM(`orderitem`.`costprice`) as costprice,
        SUM(`orderitem`.`sellingprice`) as sellingprice,
        SUM(`order`.`delivery`) as delivery,
        DATE(`order`.`confirmdate`) as `date`,
    FROM  `order`
    INNER JOIN  `orderitem`    ON `order`.`orderid` = `orderitem`.`orderid`
    GROUP BY  `date`
    ORDER BY `date`

在您的情况下也应该避免使用反引号，因为您没有单独的列名和保留字

   SELECT
        SUM(orderitem.costprice) as costprice,
        SUM(orderitem.sellingprice) as sellingprice,
        SUM(order.delivery) as delivery,
        DATE(order.confirmdate) as date,
    FROM  order
    INNER JOIN  orderitem    ON order.orderid = orderitem.orderid
    GROUP BY  date
    ORDER BY date

为了避免笛卡尔积，您可以加入聚合表

   SELECT
        SUM(t.costprice) as costprice,
        SUM(t.sellingprice) as sellingprice,
        SUM(order.delivery) as delivery,
        DATE(order.confirmdate) as date,
    FROM  order
    INNER JOIN  (
    SELECT 
        orderitem.orderid
        SUM(orderitem.costprice) as costprice,
        SUM(orderitem.sellingprice) as sellingprice
        from orderitem
        group by  orderitem.orderid
      ) t ON order.orderid = t.orderid
    GROUP BY  date
    ORDER BY date