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需要一些帮助来完成这项工作。请提供一些帮助，以确保每个ProductID始终只返回一行。我的产品表包含有关产品的基本信息，在这种情况下可以是属性。它通过 ProductCode 链接到 Properties 表。

我想要的是让查询只返回它真正应该返回的一行。本质上，该行应显示 PropertyLabel，无论 PropertyProductValues 表中是否存在该特定 propertyLabel 的值。下面的代码返回一堆实际上不应该的行，或者我不希望它。我会很感激帮助微调这个请。提前致谢。

Create Table Product 
{
    ProductID uniqueidentifier, 
    ProductName Varchar(50),
    ProductCode Varchar(50)

}

Create Table Properties
{
     PropertyID uniqueidentifier, 
     PropertyProductcode Varchar(50)

}

Create Table PropertyProductValues
{
    ID uniqueidentifier,
    PropertyID  uniqueidentifier,
    ProductID    uniqueidentifier,
    PropertyLabel Varchar(50),
    UnitID uniqueidentifier

}

Create Table unit
{
    UnitID uniqueidentifier,
    Unit Varchar(50)
}

   Select productid , PropertyLabel
PropertyValue
PropertyUnit 
from Product 
inner join Properties on ProductCode =  PropertyProductCode
left join PropertyProductValues on Properties.PropertyID = ProductProductValues.PropertyID 
left join Unit on PropertyValues.UnitID = Unit.UnitID
    Where ltrim(rtrim(lower(PropertyLabel))) = lower('Special')

样本数据

Product Table 
b0359c76-8622-4006-82f2-1b4c91a8f6b3   Brown Building   YSHJT
aba475c4-5a5c-483a-9faa-67f67ff9672d   Sket Building       GTJHD54
8f645348-8871-4fad-8c85-9fc6a1169b33    HOUSE 9           DGFS345


Properties Table

27c6485b-f7a5-4243-9304-71939230964d     DGFS345
88e911e5-bf40-4f14-89cc-4ed2984c342e     GTJHD54
d217cc14-6fcb-4251-a6d7-8fd1b3398a32      YSHJT
689cfd9d-bc87-4e23-afb3-d6cbf1e961f6       FFFSRW
bf7ae151-2e3f-4e0a-bf8b-d44ef30cf276        WYSJD

PropertyProductValues Table

6cf47434-c834-455d-a606-3d10cb9f7ab3       b0359c76-8622-4006-82f2-1b4c91a8f6b3    b0359c76-8622-4006-82f2-1b4c91a8f6b3       Storey           
82ee0f80-afe4-45c2-877c-e79ce286170f         27c6485b-f7a5-4243-9304-71939230964d   b0359c76-8622-4006-82f2-1b4c91a8f6b3       Bedrooms     
5ff7f809-6b1f-4d6c-a125-29ce67f097d7         27c6485b-f7a5-4243-9304-71939230964d    8f645348-8871-4fad-8c85-9fc6a1169b33        Bathrooms
7f634b81-1212-4223-af42-29b4dc2bafcc         27c6485b-f7a5-4243-9304-71939230964d     aba475c4-5a5c-483a-9faa-67f67ff9672d        Material
cae10884-edf0-4340-bde6-5207e28a07cc         689cfd9d-bc87-4e23-afb3-d6cbf1e961f6         b0359c76-8622-4006-82f2-1b4c91a8f6b3      Basement
83943759-39d7-406e-92ea-4202a9b1d716        bf7ae151-2e3f-4e0a-bf8b-d44ef30cf276         b0359c76-8622-4006-82f2-1b4c91a8f6b3      Storey
c045d0ff-34db-4427-9fb7-fd41fc92f310          bf7ae151-2e3f-4e0a-bf8b-d44ef30cf276         aba475c4-5a5c-483a-9faa-67f67ff9672d         balcony

Unit Table 

UNITID                                       UNIT
3a4a5216-0704-495e-b0a7-560787e0847a         kg
6b4493f6-c2e4-4682-b71d-93cb1893eb73          m
2f2b4fee-9e69-4a71-a098-36e2da71471e          l
55c8e5bf-edde-4977-ab7b-8827e337a31e          oz
19528647-bd9f-48e0-ba86-b722d5b8ab0e          cm
cee5cd46-1ae4-4b49-8b1c-9b3e0bd5270f          mm
4

1 回答 1

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如果您提供 3 个表的表结构，这将有所帮助，但原则上，要为每个 PropertyId 获取 1 行，您将执行GROUP BY PropertyId.

于 2012-10-18T19:18:25.427 回答