Inserting field text into sql query and comparing values to another table

I have an issue in Visual Web Developer 2010 that I need help with.

The code below is a Gridview Sql query where I'm extracting PART_NUMBER from various tables.  I would like to add the table name in a separate field named Comp Type.  When I use Query Builder in Configure Data Source and run Execute Query the results are what I want.  However when I run the actual program the Comp Type column is empty.

The end result should appear as follows:

PART_NUMBER     Comp Type

010-0075-06        Resistors (or Capacitors, etc.)

Sql query:

SELECT     PART_NUMBER, ('Capacitors') AS [Comp Type]
FROM         Capacitors
EXCEPT
SELECT     PART_NUMBER, ('Capacitors') AS [Comp Type]
FROM         [CIS Manufacturer Parts]
UNION
SELECT     PART_NUMBER, ('Connector') AS [Comp Type]
FROM         Connectors
EXCEPT
SELECT     PART_NUMBER, ('Connectors') AS [Comp Type]
FROM         [CIS Manufacturer Parts]
UNION
SELECT     PART_NUMBER, ('Diodes') AS [Comp Type]
FROM         Diodes
EXCEPT
SELECT     PART_NUMBER, ('Diodes') AS [Comp Type]
FROM         [CIS Manufacturer Parts]
UNION
SELECT     PART_NUMBER, ('ICs') AS [Comp Type]
FROM         ICs
EXCEPT
SELECT     PART_NUMBER, ('ICs') AS [Comp Type]
FROM         [CIS Manufacturer Parts]
UNION
SELECT     PART_NUMBER, ('Inductors') AS [Comp Type]
FROM         Inductors
EXCEPT
SELECT     PART_NUMBER, ('Inductors') AS [Comp Type]
FROM         [CIS Manufacturer Parts]
UNION
SELECT     PART_NUMBER, ('Misc') AS [Comp Type]
FROM         Misc
EXCEPT
SELECT     PART_NUMBER, ('Misc') AS [Comp Type]
FROM         [CIS Manufacturer Parts]
UNION
SELECT     PART_NUMBER, ('Relays') AS [Comp Type]
FROM         Relays
EXCEPT
SELECT     PART_NUMBER, ('Relays') AS [Comp Type]
FROM         [CIS Manufacturer Parts]
UNION
SELECT     PART_NUMBER, ('Resistors') AS [Comp Type]
FROM         Resistors
EXCEPT
SELECT     PART_NUMBER, ('Resistors') AS [Comp Type]
FROM         [CIS Manufacturer Parts]
UNION
SELECT     PART_NUMBER, ('Switches') AS [Comp Type]
FROM         Switches
EXCEPT
SELECT     PART_NUMBER, ('Switches') AS [Comp Type]
FROM         [CIS Manufacturer Parts]
UNION
SELECT     PART_NUMBER, ('Transformers') AS [Comp Type]
FROM         Transformers
EXCEPT
SELECT     PART_NUMBER, ('Transformers') AS [Comp Type]
FROM         [CIS Manufacturer Parts]
UNION
SELECT     PART_NUMBER, ('Transistors') AS [Comp Type]
FROM         Transistors
EXCEPT
SELECT     PART_NUMBER, ('Transistors') AS [Comp Type]
FROM         [CIS Manufacturer Parts]
UNION
SELECT     PART_NUMBER, ('Crystals and Oscillators') AS [Comp Type]
FROM         [Crystals and Oscillators]
EXCEPT
SELECT     PART_NUMBER, ('Crystals and Oscillators') AS [Comp Type]
FROM         [CIS Manufacturer Parts]
ORDER BY PART_NUMBER

The asp portion is below and I suspect I'm missing something:

<asp:TemplateField><HeaderTemplate>
                    Comp Type</HeaderTemplate><ItemTemplate></ItemTemplate></asp:TemplateField>

I have a separate table (CIS Manufacturer Parts) that contains manufacturer data for the above parts.  Multiple manufacturer rows can exist.  The connection between tables in the PART_NUMBER field.  What I would like to do is make this query add the table name to the gridview output listing only parts without manufacturer data and the table they can be found in.

This is a lot for a newbie so I will appreciate any help, thanks!