Redundant transpose. Case is not enough to solve my problem
Telling us that you are using a CASE statement but not showing us the actual code that you're using doesn't help us much.  Assuming that "Result Table" is the desired output and that you want to use the old-style MAX(CASE syntax to do your pivot rather than using the newer PIVOT operator

SELECT emp_id,
       emp_name,
       nvl( max( case when sal_paid = 'JAN' then'Y' else NULL end ), 'N' ) jan,
       nvl( max( case when sal_paid = 'FEB' then'Y' else NULL end ), 'N' ) feb,
       nvl( max( case when sal_paid = 'MAR' then'Y' else NULL end ), 'N' ) mar,
       nvl( max( case when sal_paid = 'APR' then'Y' else NULL end ), 'N' ) apr
  FROM your_table
 GROUP BY emp_id, emp_name