SELECT 1 WHERE 
  EXISTS (
    SELECT 1 FROM managed_policies WHERE 
        domain='com.apple.SoftwareUpdate' AND 
        name='AutomaticCheckEnabled' AND 
        (value = 1 OR value = 'true') AND 
        username = ''
    )
  AND NOT EXISTS (
    SELECT 1 FROM managed_policies WHERE 
        domain='com.apple.SoftwareUpdate' AND 
        name='AutomaticCheckEnabled' AND 
        (value != 1 AND value != 'true')
    );