Write a query to return the last name of all employees whose names have exactly 7 characters.

- Write a query to return the first name of all employees who have both a “r” and a “s” in their first or last name.

- Write a query to display the first and last name of employees having “e” as the second character of their last name.

- Write a query to display the name (first_name, last_name) and department ID for all employees in department 50 or 100 in ascending order.

- Write a query to display the name (first_name, last_name) and salary of all employees who were hired in March.

regions REGION_ID NUMBER REGION_NAME VARCHAR2(25) departments DEPARTMENT_ID DEPARTMENT NAME VARCHAR2(30) MANAGER_ID LOCATION ID NUMBER NUMBER NUMBER countries COUNTRY_ID CHAR(2) COUNTRY_NAME VARCHAR2(40) REGION_ID NUMBER employees EMPLOYEE ID FIRST_NAME LAST_NAME EMAIL PHONE NUMBER HIRE DATE JOB ID SALARY COMMISSION_PCT MANAGER ID DEPARTMENT_ID NUMBER VARCHAR2(20) VARCHAR2(25) VARCHAR2(25) VARCHAR2(20) DATE VARO NUMBER NUMBER NUMBER NUMBER locations LOCATION_ID NUMBER STREET_ADDRESS VARCHAR2(25) VARCHAR2(12) VARCHAR2(30) STATE_PROVINCE VARCHAR2(12) COUNTRY_ID CHAR(2) POSTAL CODE CITY jobs JOB_ID JOB_TITLE VARCHAR2(10) VARCHAR2(35) MIN SALARY NUMBER MAX_SALARY NUMBER