I just need a sql querry which should return updated databse column names
Here I am having three tables 
EMP
EMP1
EMP2

Three tables having similar structure. But emp2 is having one extra column from other two tables

EMP
empno empname dname
1 a aa
2 b bb
c c cc

EMP1
empno empname dname
1 a ab
2 c bb
c d ee

I Have to compare these two tables and I have to insert the rows into emp2 if any rows got updated

EMP2
empno empname dname updated_columnss
1 a ab dname
2 c bb ename
c d ee ename, dname


I have written sql in the foillowing manner. Its executing fine. But I am having 217 columns in a table and it should be dynamically executed.

INSERT INTO 
    EMP2(DNAME,EMPNAME,EMPNO, UPDATED_COLUMNS) 
            ( SELECT     
              t1.DNAME,
              t1.EMPNAME,
              t1.EMPNO,
              t3.UPDATEDCOLS 
   FROM EMP t1 ,
        EMP1 t2 ,
        ( select t1.EMPNO , 
                       RTRIM 
                         ( 
                          CASE WHEN( (t1.DNAME <> t2.DNAME) OR 
                            (t1.DNAME IS NULL AND t2.DNAME IS NOT NULL ) OR
                            (t1.DNAME IS NOT NULL AND t2.DNAME IS NULL )) 
                            THEN ' DNAME ,'ELSE NULL END || 

                 CASE WHEN( (t1.EMPNAME <> t2.EMPNAME) OR 
                           (t1.EMPNAME IS  NULL AND t2.EMPNAME IS NOT NULL ) OR 
                            (t1.EMPNAME IS  NOT NULL AND t2.EMPNAME IS NULL )) 
                           THEN ' EMPNAME , 'ELSE NULL END , ' , ' )
as updatedcols 
                               from EMP t1 ,EMP1 t2 where t1.EMPNO = t2.EMPNO ) t3 
WHERE t1.empno= t2.empno and t1.empno=t3.empno and
( (t1.DEPTNO <> t2.DEPTNO OR (t1.DEPTNO IS NULL AND t2.DEPTNO IS NOT NULL ) OR (t1.DEPTNO IS NOT NULL AND  t2.DEPTNO IS NULL )) OR 
(t1.DNAME <> t2.DNAME OR (t1.DNAME IS NULL AND t2.DNAME IS NOT NULL ) OR (t1.DNAME IS NOT NULL AND t2.DNAME IS NULL )) OR 
(t1.EMPNAME <> t2.EMPNAME OR (t1.EMPNAME IS NULL AND t2.EMPNAME IS NOT NULL ) OR (t1.EMPNAME IS NOT NULL AND t2.EMPNAME IS NULL )) OR 
(t1.EMPNO <> t2.EMPNO OR (t1.EMPNO IS NULL AND t2.EMPNO IS NOT NULL ) OR (t1.EMPNO IS NOT NULL AND t2.EMPNO IS NULL )));