Using joins in a dataloader export and SOQL syntax help

I have a specifc query I would like to export and I am a complete novice to SOQL syntax.

What I need is all instances of an object that does not have attached to them a PDF that follows the format [Name] & ‘.pdf’

Given the structure of these in salesforce, if I was to achieve this in SQL Server I would do the below:
SELECT
Object.id
      Object.Name
FROM Object
LEFT JOIN
      (SELECT
            Attachments.ParentID
      FROM Attachments
      INNER JOIN Object ON
            Attachments.ParentID = Object.ID
      WHERE Attachments.Name = Object.Name + '.pdf') AS PDF ON
            PDF.ParentID = Object.id
WHERE PDF.ParentID is null

Is this possible through the data loader in any way?

Thanks