Hello Sourav,

self._cr.execute('select * from std_table_print')   this means only the query executed
after that you have to fetch from cursor

self._cr.fetch()

or 

self._cr.fetchall()

or

self._cr.fetchone()

To fetch data from the employee module you can use this function:

It will execute a SQL command and fetch all the data into a list of tuple formats and then convert it into dictionary format.

    @api.model
    def get_department_employee(self):
        cr = self._cr
        cr.execute("""select department_id, hr_department.name,count(*) 
            from hr_employee join hr_department on hr_department.id=hr_employee.department_id 
            group by hr_employee.department_id,hr_department.name""")
        fetch_data = cr.fetchall()
        data = []
        for i in range(0, len(fetch_data)):
            data.append({'label': fetch_data[i][1], 'value': fetch_data[i][2]})
        return data