SELECT *
  FROM (
         (SELECT DISTINCT devname, dev_id
            FROM diskdevs as d
           WHERE devname NOT LIKE '%:%'
             AND d.host_id = 1 -- ONLY one host
         ) AS z1
         CROSS JOIN
         (SELECT DISTINCT time
            FROM iostat AS i, diskdevs as d
           WHERE i.dev_id = d.dev_id
         ) AS z2
      )
;