String getExistingFileEntry = "select * from test "
                                    + " where a = ? and b = ? and date < DATE_SUB(NOW(), INTERVAL 1 DAY)"
                                    + "order by id"
                                    + "limit 1";

PreparedStatement pstVerify = null;
            pstVerify = con.prepareStatement(getExistingFileEntry);
            pstVerify.setString(1, a);
            pstVerify.setString(2, b);

            ResultSet rsFirst =null;
            String existingSum = null;
            //execute select SQL statement
                    rsFirst = pstVerify.executeQuery();

com.mysql.jdbc.exceptions.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '1' at line 1