Linking Support groups from dbo.ci to dbo.WorkOrder

Linking Support groups from dbo.ci to dbo.WorkOrder

I can get the created support groups by 

select * from [dbo].[CI] where CITYPEID = 8
which gives me the columns
  1. CIID
  2. CITYPEID 
  3. CINAME
  4. DESCRIPTION
  5. LABEL
  6. CREATEDDATE
  7. LASTMODIFIED
  8. VERSION
  9. LIFECYCLEGROUPIDENTIFIER
  10. SITEID

How can I link this to the primary workOrder table e.g.
select * from dbo.WorkOrder ?
Fot most entries in dbo.WorkOrder the CIID column is NULL, so I assume this is not the way to do it.

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