select count(*) from tablename where count(*) >1  group by empno;

( jst checkin for to count duplicate records if not  jst send reply to me)

thanx

The syntax in the previous answer (where count(*) > 1) is very questionable. suppose you think that you have duplicate employee numbers. there's no need to count them to find out which values were duplicate but the followin SQL will show only the empnos that are duplicate and how many exist in the table:

Select empno, count(*)

from    employee

group by empno

having count(*) > 1

Generally speaking aggregate functions (count, sum, avg etc.) go in the HAVING clause. I know some systems allow them in the WHERE clause but you must be very careful in interpreting the result.  WHERE COUNT(*) > 1 will absolutely NOT work in DB2 or ORACLE.  Sybase and SQLServer is a different animal.

The soln given does not seem to work,

error says group function not allowed in where clause

That's exactly what I said. You can't have any aggregate function in a where clause. They must be in a having clause prededed by group by.

The approach is wrong anyway.

Select empno

from   emp

group by empno

having count(*) > 1