Question

我有下表

MySQL [distributor]> select * from orderitems;
+-----------+------------+---------+----------+------------+
| order_num | order_item | prod_id | quantity | item_price |
+-----------+------------+---------+----------+------------+
|     20005 |          1 | BR01    |      100 |       5.49 |
|     20005 |          2 | BR03    |      100 |      10.99 |
|     20006 |          1 | BR01    |       20 |       5.99 |
|     20006 |          2 | BR02    |       10 |       8.99 |
|     20006 |          3 | BR03    |       10 |      11.99 |
|     20007 |          1 | BR03    |       50 |      11.49 |
|     20007 |          2 | BNBG01  |      100 |       2.99 |
|     20007 |          3 | BNBG02  |      100 |       2.99 |
|     20007 |          4 | BNBG03  |      100 |       2.99 |
|     20007 |          5 | RGAN01  |       50 |       4.49 |
|     20008 |          1 | RGAN01  |        5 |       4.99 |
|     20008 |          2 | BR03    |        5 |      11.99 |
|     20008 |          3 | BNBG01  |       10 |       3.49 |
|     20008 |          4 | BNBG02  |       10 |       3.49 |
|     20008 |          5 | BNBG03  |       10 |       3.49 |
|     20009 |          1 | BNBG01  |      250 |       2.49 |
|     20009 |          2 | BNBG02  |      250 |       2.49 |
|     20009 |          3 | BNBG03  |      250 |       2.49 |
+-----------+------------+---------+----------+------------+
18 rows in set (0.098 sec)

我能够将指定订单的总价总结为；

MySQL [distributor]> select order_num, sum(quantity*item_price) 
  as total_price from orderitems where order_num = 20008;
+-----------+-------------+
| order_num | total_price |
+-----------+-------------+
|     20008 |      189.60 |
+-----------+-------------+
1 row in set (0.026 sec)

如何汇总每个订单的总价并将它们一起显示？

Answer 1

使用GROUP BY：

select order_num, sum(quantity*item_price) as total_price
from orderitems group by order_num

Answer 2

一个SELECT语句子句，将查询结果分为几组行，通常是为了对每一组执行一个或多个聚合。 SELECT语句每组返回一行。

所以一切都很好，只需要按order_num分组

 select order_num, sum(quantity*item_price) as total_price from orderitems
    group by order_num

Answer 3

如果要显示所有包含订单明细的订单的总价，可以从选择中删除订单编号：-

select sum(quantity*item_price) as total_price from orderitems;

但是，如果要显示每个订单的所有订单总价，则可以使用以下查询：-

select order_num, sum(sum(quantity*item_price)) OVER() as total_price 
from orderitems 
group by order_num;

汇总指定项的总数

3 个答案: