How to get number of matching colums count in the same table as another column?
With window functions, this would be almost trivial to add as a column in a query:

COUNT(*) OVER (PARTITION BY status) AS status_count


Since MySQL hasn't implemented them (you'll have to wait, they may be in the next version), you'll need something more complex now. It can be done with a derived table - to calculate these counts - and then join to the base table:

SELECT 
    t.id, t.box_name, t.diIndex, t.diMode, t.diStatus, t.status,
    g.status_count, t.last_updated
FROM
    tableX AS t
  JOIN
    ( SELECT status, COUNT(*) AS status_count
      FROM tableX 
      GROUP BY status
    ) AS g
  ON
    t.status = g.status ;