CREATE TABLE departments (DEPARTMENT_ID NUMBER, DEPARTMENT_NAME VARCHAR2, MANAGER_ID NUMBER, LOCATION_ID NUMBER)
CREATE TABLE locations (LOCATION_ID NUMBER, STREET_ADDRESS VARCHAR2, POSTAL_CODE VARCHAR2, CITY VARCHAR2, STATE_PROVINCE VARCHAR2, COUNTRY_ID VARCHAR2)
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 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 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)

For those employees who was hired before 2002-06-21, give me the trend about employee_id over hire_date , and I want to order X in asc order.
SELECT HIRE_DATE, EMPLOYEE_ID FROM employees WHERE HIRE_DATE < '2002-06-21' ORDER BY HIRE_DATE
SELECT "HIRE_DATE", "EMPLOYEE_ID" FROM "employees" WHERE "HIRE_DATE" < '2002-06-21' ORDER BY "HIRE_DATE"