Mysql 从两个表中获取 SUM 和 COUNT 值

Question

这是我的 table

table 1: 订单

id  total order_date
1   200    2016-04-22
2   300    2016-04-22

table 2: order_products

 id  order product_id qty
  1    1       1       2
  2    1       2       1
  3    2       2       2
  4    2       1       2

我的结果应该是

tot_order total_amount  prd_qty
 2      500             7

我的查询是

    SELECT COUNT(ddo.id) AS tot_order, 
           SUM(ddo.total) AS total_amount, 
           (SELECT SUM(dop.qty) 
            FROM  order_products dop 
            WHERE dop.order=ddo.id) AS prd_qty  
    FROM orders ddo 
    WHERE DATE(ddo.`order_date`) BETWEEN '2016-04-22' AND '2016-04-22'

我可以得到total_order和total_amount，但是如何得到prd_qty？

谢谢

Answer 1

也许您缺少 GROUP BY 子句

(SELECT SUM(dop.qty) FROM  order_products dop WHERE dop.order=ddo.id GROUP BY dop.order)

Answer 2

您应该使用子查询来计算 prd_qty:

SELECT SUM(dop.qty) as prd_qty,  dop.order 
FROM  order_products dop 
GROUP BY dop.order

每个订单计数 prd_qty。
完整查询：

SELECT COUNT(ddo.id) AS tot_order, 
       SUM(ddo.total) AS total_amount, 
       sum(op.prd_qty) as prd_qty
FROM   orders ddo 
       JOIN 
       (
            SELECT SUM(dop.qty) as prd_qty,  dop.order 
            FROM  order_products dop 
            GROUP BY dop.order
       ) as op ON (op.order = ddo.id)
WHERE  DATE(ddo.`order_date`) BETWEEN '2016-04-22' AND '2016-04-22'

Answer 3

此查询适合您。

SELECT COUNT(od.`id`) AS tot_order, SUM(od.`total`) AS total_amount, tablea.prd_qty
FROM orders od JOIN (
                SELECT SUM(op.`prd_qty`) AS prd_qty
                FROM orders od INNER JOIN order_products op
                ON od.`id`=op.`order`
                WHERE DATE(od.`order_date`) BETWEEN '2016-04-22' AND '2016-04-22' 
) tablea
WHERE DATE(od.`order_date`) BETWEEN '2016-04-22' AND '2016-04-22'

要获得 prd_qty，您必须运行我在 join 之后的小括号中添加的子查询。

Answer 4

看起来你想把 order_products 加起来变成 orders 然后加起来结果。

我会在查询中遵循这个概念：

SELECT COUNT(*) tot_order,
       SUM(os.total) total_amount,
       SUM(os.o_prd_qty) prd_qty
  FROM (       
    SELECT o.id,
           o.total,
           SUM(op.qty) o_prd_qty
      FROM orders o
      JOIN order_products op
        ON op.order = o.id
     WHERE o.order_date >= :start_date
       AND o.order_date < :end_date + INTERVAL 1 DAY
  GROUP BY o.id
       ) os

如果你想要单独的 orders 和他们的 prd_qty 只是运行内部查询。

我还修复了您的日期逻辑，以便优化器可以使用 order_date 上的索引。通常，如果将一列包装在比较的一侧的函数中，则该列上的任何索引都不可用。

附带说明一下，我会仔细研究一下您的命名约定。每个人都有自己的喜好，但你应该与这些问题保持一致：

缩写? - tot, total, prd, product, qty
附加 _id 外键？ - order_products.order, order_products.product_id
在列中包含 table 名称？ - orders.total、orders.order_date

遵循约定可以使您的数据库更易于导航和使用。否则在编写每个查询时都会返回到模式！

就我个人而言，我通常不会缩写，请在列中附加 _id 并且不要包含 table 名称。

Answer 5

获得答案的最简单的查询是，这就像一把刀穿过黄油。

但是，如果为列 orders(id) 创建索引会更漂亮。如果它已经是一个主键列索引将不需要只有当您相信您的数据数量会增加时才会建立索引

select count(o.id) as tot_order ,
sum(o.total) as total_amount,
(select sum(p.qty) from orders o join order_product p on o.id=p.order) as prd_qty     
from orders o;

Answer 6

This should work fine for you.

select sum(order_id) orders, sum(total) total, sum(qty) prd_qty
from (select count(o.id) order_id, sum(o.total) total,
(select sum(qty) from order_products op where o.id = op.`order`) qty
from orders o group by o.id) x;

相当简单。

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