ข้อ 1

select initcap(last_name) as Name,length(last_name) as Length
from hr.employees
where last_name like 'J%' or last_name like 'A%' or last_name like 'M%'

ข้อ 2

select employee_id,last_name,salary,salary+salary*0.155 as "New Salary"
from hr.employees;

ข้อ 3

select employee_id,hire_date,
    concat(concat(concat(substr((hire_date),4,3),' '|| substr((hire_date),1,2)),' , 20'),substr((hire_date),8,2)) 
    as "hire_date formatted"
from hr.employees;

ข้อ 4

select last_name,TRUNC((SYSDATE - hire_date) / 7) as "TENURE (in week)"
from hr.employees
where  department_id = 90

ข้อ 5

select employee_id,hire_date,
       add_months(hire_date,6 )  as "REVIEW",
       NEXT_DAY(hire_date,'FRIDAY') as "Next Hire Date",
       LAST_DAY(hire_date) as "Last Hire Date",
       TRUNC((SYSDATE - hire_date) / 365)  as "TENURE (in years)"
from hr.employees 
where   TRUNC((SYSDATE - hire_date) / 365) > 15