来计算折扣？

-2

有3个表 - 折扣（折扣）的客户端（客户端）和订单（订单）来计算折扣？

折扣

------------------------------------------------ 
|id_discount | count_orders | percent_discount | 
------------------------------------------------ 
|   1 |   5 |    1,5 | 
|   2 |   10 |    2,5 |

客户

------------------------------------------------ 
| id_client | Name  |  Surname  | 
------------------------------------------------ 
|   1 | Ivan   | Petrov   | 
|   2 | Vasya  | Vasev   |

订单

------------------------------------------------ 
| id   | order_sum | id_client  | 
------------------------------------------------

问题如何计算总金额，给定数量或客户提供的服务？如果订单总数5及以上，折扣为1.5％，如果10以上，则为2.5％。否则，没有折扣。在此先感谢

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2016-06-09 Mr.Steps

您的客户表与折扣表没有任何关系。添加它。然后....非常容易，您可以计算此客户端的订单总数或订单数（例如在存储过程中）和更新表客户端。您可以在更新后的触发订单中执行此过程。你需要一个例子吗？ –

以同样的方式，您可以计算折扣，而无需认同'clients-> discount'。在需要时调用存储过程。 –

@ValMarinov不需要提及折扣。从表格定义和问题描述可以看出，折扣取决于您订单中的物品数量。 –

-1

您可以使用PROCEDURE和CURSOR来解决这个问题：

DELIMITER $$ 
CREATE PROCEDURE `getDiscount`(IN _orderSum INT(11)) 
    BEGIN 
    DECLARE countOrders INT(11) DEFAULT 0; 
    DECLARE percentDiscount DOUBLE DEFAULT 0; 
    DECLARE done INT(1); 
    DECLARE cur CURSOR FOR SELECT count_orders, percent_discount FROM Discount ORDER BY count_orders DESC; 
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1; 
    SET done = 0; 
    OPEN cur; 
    discountLoop: LOOP 
     FETCH cur INTO countOrders, percentDiscount; 
     IF done = 1 THEN LEAVE discountLoop; END IF; 
     IF _orderSum >= countOrders THEN 
      SELECT percentDiscount AS percent_discount FROM dual; 
      SET done = 1; 
     END IF; 
    END LOOP discountLoop; 
    CLOSE cur; 
    END$$ 
DELIMITER ;

来源

2016-06-10 09:32:07

您正在使用MySQL语法来回答Firebird/Interbase问题。 –

对不起，我在阅读这个问题时不小心。 –

为此才能正常工作，你需要为0订单折扣为好。插入折扣（count_orders，percent_discount）值（0,0）;

要查找客户折优惠给定ID，这样的事情：

select d.percent_discount 
from Discount d 
where d.count_orders = isnull(
     (select max(count_orders) 
     from Discount dI where count_orders <= (
      select count(1) from Orders oI where oI.id_client = 1)), 0)

获取每个客户的优惠：

select c.id_client as client_id, 
     (select d.percent_discount 
     from Discount d 
     where d.count_orders = isnull(
      (select max(count_orders) 
      from Discount dI where count_orders <= (
       select count(1) from Orders oI where oI.id_client = c.id_client)), 0)) as discount 
from Clients c

与选择相结合，发现价格每个订单折扣：

select o.id, 
c.name, 
c.surname, 
o.order_sum, 
(o.order_sum - (o.order_sum * client_discount.discount/100)) as sumWithDiscount 
from Orders o join Clients c on o.id_client = c.id_client 
    join (select cI.id_client, 
       (select d.percent_discount 
       from Discount d 
       where d.count_orders = isnull(
        (select max(count_orders) 
        from Discount dI where count_orders <= (
          select count(1) from Orders oI where oI.id_client = cI.id_client)), 0)) as discount 
      from Clients cI) as client_discount on client_discount.id_client = c.id_client

来源

2016-06-10 09:53:05 Tobb

来计算折扣？

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