WITH CTE_MIN AS
(SELECT NAME, RUN_START, LK1, DESCR, 
	ROW_NUMBER() OVER (PARTITION BY NAME, DESCR ORDER BY RUN_START ASC) AS RowNum
FROM #DaTable
),
CTE_MAX AS
(SELECT NAME, RUN_END, LK2, DESCR, 
	ROW_NUMBER() OVER (PARTITION BY NAME, DESCR ORDER BY RUN_START DESC) as RowNum
FROM #DaTable
)
SELECT CTE_MIN.NAME, CTE_MIN****N_START, CTE_MAX****N_END, CTE_MIN.LK1, CTE_MAX.LK2, CTE_MIN.DESCR
FROM CTE_MIN
	INNER JOIN CTE_MAX ON
		CTE_MIN.NAME = CTE_MAX.NAME AND
		CTE_MIN.DESCR = CTE_MAX.DESCR
WHERE CTE_MIN.RowNum = 1 AND
	CTE_MAX.RowNum = 1

select x.name,
       x.r_un_start,
       x.r_un_end,
       ( SELECT lk1 FROM mytable m
         WHERE m.`desc` = x.`desc` AND m.r_u_start = x.r_un_start
         LIMIT 1
       ) lk1,
       ( SELECT lk2 FROM mytable m
         WHERE m.`desc` = x.`desc` AND m.r_un_end = x.r_un_end
         LIMIT 1
       ) lk2,
       x.`desc`
FROM (
  SELECT name, `desc`, min( run_start) run_start, max(run_end) run_end
  FROM mytable
  GROUP BY `desc`
) x;