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Get column from derived table
Message
De
11/06/2014 13:56:49
 
 
Information générale
Forum:
Visual FoxPro
Catégorie:
Autre
Versions des environnements
Visual FoxPro:
VFP 9 SP2
OS:
Windows Server 2012
Network:
Windows 2008 Server
Database:
MS SQL Server
Application:
Web
Divers
Thread ID:
01601694
Message ID:
01601717
Vues:
30
>>>>>>>Does it make sense?
>>>>>>
>>>>>>You need a simple LEFT JOIN, e.g.
>>>>>>select Cust.ID, Cust.Name, T.Descr as TypeDescr
>>>>>>from Customer cust LEFT JOIN Types T ON Cust.Type_ID = T.Descr
>>>>>
>>>>>I tried it. LEFT JOIN creates a query where you have as many records for each record in CUSTOMER as there are TYPEs. Didn't work for me.
>>>>
>>>>Something doesn't make sense here.
>>>>
>>>>If type_ID in the Customer table is an FK and Type_ID in the Types table is primary key, then LEFT JOIN should only bring one row per customer with the type description.
>>>>
>>>>May be Type_ID is not the primary key in the Types table?
>>>
>>>Correct. See my reply to Rob.
>>
>>I saw the reply. So, which one of the descriptions per "type_id" do you want? Why do you allow duplicates in that lookup table? Sounds like a bad design.
>
>Now you are knocking my design; I am going to unfriend you :)
>But seriously I see that I have a problem that I need to resolve.
>Thank you.

Key values should almost never be user editable. If the user needs to be able to change the type id, you should have another field in the database to act as the actual primary key.
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