CREATE TABLE countries (COUNTRY_ID VARCHAR2, COUNTRY_NAME VARCHAR2, REGION_ID NUMBER)
CREATE TABLE jobs (JOB_ID VARCHAR2, JOB_TITLE VARCHAR2, MIN_SALARY NUMBER, MAX_SALARY NUMBER)
CREATE TABLE departments (DEPARTMENT_ID NUMBER, DEPARTMENT_NAME VARCHAR2, MANAGER_ID NUMBER, LOCATION_ID NUMBER)
CREATE TABLE job_history (EMPLOYEE_ID NUMBER, START_DATE DATE, END_DATE DATE, JOB_ID VARCHAR2, DEPARTMENT_ID NUMBER)
CREATE TABLE regions (REGION_ID NUMBER, REGION_NAME VARCHAR2)
CREATE TABLE employees (EMPLOYEE_ID NUMBER, FIRST_NAME VARCHAR2, LAST_NAME VARCHAR2, EMAIL VARCHAR2, PHONE_NUMBER VARCHAR2, HIRE_DATE DATE, JOB_ID VARCHAR2, SALARY NUMBER, COMMISSION_PCT NUMBER, MANAGER_ID NUMBER, DEPARTMENT_ID NUMBER)
CREATE TABLE locations (LOCATION_ID NUMBER, STREET_ADDRESS VARCHAR2, POSTAL_CODE VARCHAR2, CITY VARCHAR2, STATE_PROVINCE VARCHAR2, COUNTRY_ID VARCHAR2)

You can give me a pie chart, that groups and counts the country name.
SELECT COUNTRY_NAME, COUNT(COUNTRY_NAME) FROM countries GROUP BY COUNTRY_NAME
SELECT "COUNTRY_NAME", COUNT("COUNTRY_NAME") FROM "countries" GROUP BY "COUNTRY_NAME"