Question

我可以将它们一起添加到一起工作，用户可以选择对国家1或2有效并且两者同时我需要这些一起工作如果可能的话当用户选择两者时我需要它来显示两个测量值

我无法创建一个新表，因此我基本上需要根据哪个国家/地区和单位价格基础来填充

,CASE 
    WHEN bd.Validforcountry = 1 and BD.UnitpriceBase = 1
        THEN '100 ml'
    WHEN bd.Validforcountry = 1 and BD.UnitpriceBase = 2
        THEN '1 l'
    WHEN bd.Validforcountry = 1 and BD.UnitpriceBase = 3
        THEN '100 g'
    WHEN bd.Validforcountry = 1 and  BD.UnitpriceBase = 4
        THEN '1 Kg'
    WHEN bd.Validforcountry = 1 and BD.UnitpriceBase = 5
        THEN '750 ml'
    ELSE BD.UnitpriceBase
    END AS 'Unit price Declaration'


,CASE 
    WHEN bd.Validforcountry = 2 and BD.UnitpriceBase = 1
        THEN '100 ml'
    WHEN bd.Validforcountry = 2 and BD.UnitpriceBase = 2
        THEN '1 l'
    WHEN bd.Validforcountry = 2 and BD.UnitpriceBase = 3
        THEN '100 g'
    WHEN bd.Validforcountry = 2 and  BD.UnitpriceBase = 4
        THEN '1 Kg'
    WHEN bd.Validforcountry = 2 and BD.UnitpriceBase = 5
        THEN '750 ml'
    ELSE BD.UnitpriceBase
    END AS 'Unit price Declaration'

Answer 1

只需创建一个新表，而不是创建复杂的CASE WHEN，这样就可以通过简单的JOIN选择正确的值。像这样：

CREATE TABLE UnitPriceDeclaration
(
    Country int,
    UnitPriceBase int,
    UnitPriceDeclaration varchar(20),
    PRIMARY KEY (Country, UnitPriceBase)
);

通过这种方式，您可以像这样编写查询（虚拟连接，我不了解您的其他表格）：

SELECT t1.someField, 
       t2.someOtherField, 
       t1.UnitPriceBase, 
       t2.Country, 
       upd.UnitPriceDeclaration
FROM oneTable t1,
INNER JOIN anotherTable t2 ON ...
INNER JOIN UnitPriceDeclaration upd ON upd.Country = t2.Country AND upd.UnitPriceBase = t1.UnitPriceBase -- maybe LEFT JOIN
WHERE...

这使您可以保持灵活性并根据需要添加/更改任意数量的国家/地区，UPB或UPD，而无需更改数据以外的任何内容。像你一样使用CASE WHEN，你必须在每次发生变化时（可能在多个地方）更改你的代码。

您的编辑主张此解决方案。看到所有那些重复的值？

所以，让我们说你要显示两个UPD，一个用于英国，一个用于IRE。你只需要做这样的事情：

SELECT t1.someField, 
       t2.someOtherField, 
       t1.UnitPriceBase, 
       t2.Country, 
       upduk.UnitPriceDeclaration as UPD_UK,
       updire.UnitPriceDeclaration as UPD_IRE
FROM oneTable t1,
INNER JOIN UnitPriceDeclaration upduk ON upd.UnitPriceBase = t1.UnitPriceBase AND upd.Country = 1
INNER JOIN UnitPriceDeclaration updire ON upd.UnitPriceBase = t1.UnitPriceBase AND upd.Country = 2
WHERE...

两个条件的案例陈述

1 个答案: