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Editorial Team
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Asked: 2026-05-13T06:15:17+00:00

I am working with a SharePoint web part that I am designing in C#.

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I am working with a SharePoint web part that I am designing in C#. I need to query a SQL Server 2005 database to return the names of machines that are associated with a particular customer, selected by the user.

The problem is that there are different types of machines, and the names themselves are stored in several other tables. Here is the structure as it pertains to this question:

I have a table “customerInfo” which contains the ID and name of each customer. The ID is the primary key.

A table “machineIDs” links the customer IDs to the corresponding machine IDs. The machine ID is the primary key.

I have two tables for two types of machines, “machine1” and “machine2.” machine1 contains the name of the machine itself, but machine2 only contains the ID of the type of machine it is. With both of these tables, the machine ID is the primary key.

Then I have a table “specialtyMachine.” This table contains the name of the machine and the ID of this type of machine. The primary key here is a type ID, which identifies the type of machine, whereas the machine ID identifies the specific machine.

What I need to do is pull the machine name from machine1 and specialtyMachine, given just the customer ID. I’m not sure whether it’s possible to do this with a complex join directly within the query, or if I will need to apply logic in the web part to pull this information together.

I would also like to know how I can think about this in terms of a generic model. I’d like to be able to recognize this and apply it generically in the future, as I’m sure it’s a fairly common problem that I just haven’t dealt with yet. Thank you.

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1 Answer

  1. Editorial Team

    Based on your new schema information I’m guessing this is what you want:

    select *
from customerinfo c
left join machineids mids on c.customerid = mids.customerid
left join machine1 m1 on mids.machineid = m1.machineid
left join spcialtymachine sm on mids.machineid = sm.machineid -- or m1.machineid = sm.machineid
left join machine2 m2 on sm.typeid = m2.typeid

    note: if you are using this in a stored procedure with an @customerid as a parameter you can add a where c.customerid = @customerid to the end.

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