Oracle complex query help required
SQL> desc jtoom.mnp_port_nos_prbt_view;
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 LSA                                                VARCHAR2(144)
 MSISDN                                             VARCHAR2(144)
 RECIPIENT                                          VARCHAR2(144)
 DONOR                                              VARCHAR2(144)
 LRN                                                VARCHAR2(144)
 DT_STAMP                                           DATE

select column_name, max(dt_stamp) max_dt_stamp
from table_or_view
group by column_name

SELECT DISTINCT A.Column_Name, A.Dt_Stamp
FROM jtoom.mnp_port_nos_prbt_view A
WHERE A.Dt_Stamp = (SELECT Max(B.Dt_Stamp) FROM jtoom.mnp_port_nos_prbt_view B WHERE B.Column_Name = A.Column_Name)