Data stored in DB like below				
ID	Dept	From_date	To_date	
ID_123	Dep_1	1-Jan-15	31-May-15	
ID_123	Dep_2	1-Jun-15	31-Dec-99	
				
Need to get results as below				
ID	Dept	From_date	To_date	Comments
ID_123	Dep_1	1-Jan-15	31-May-15	
ID_123	Dep_1	1-Feb-15	31-May-15	
ID_123	Dep_1	1-Mar-15	31-May-15	
ID_123	Dep_1	1-Apr-15	31-May-15	
ID_123	Dep_1	1-May-15	31-May-15	
ID_123	Dep_2	1-Jun-15	31-Dec-99	Latest Record
ID_123	Dep_2	1-Jul-15	31-Dec-99	Till current Month
ID_123	Dep_2	1-Aug-15	31-Dec-99	Till current Month