1. Display the employee last name, job ID, and start date of employees hired between February 20,
1998, and May 1, 1998. Order the query in ascending order by start date.

Ans: 
SELECT Last_Name, Job_ID, Hire_Date as Start_Date
FROM employees
WHERE Hire_date BETWEEN '1998-02-20' AND '1998-05-01' ORDER BY Hire_Date;


2. Display the last name and department number of all employees in departments 20 and 50 in
alphabetical order by name.

Ans:

SELECT Last_Name, Department_ID
FROM employees
WHERE Department_ID IN (20, 50)
ORDER BY Last_Name;


3. Display the last name and hire date of every employee who was hired in 1994.

Ans:

SELECT Last_Name, Hire_Date
FROM employees
WHERE Hire_Date LIKE '%94';


4. Display the last name, salary, and commission for all employees who earn commissions.
Sort data in descending order of salary and commissions.

Ans:

select Last_Name, Salary, Commission_pct
from employees
where Commission_pct is not null
order by Salary, Commission_pct;



5. Display the last name of all employees who have an a and an e in their last name.

Ans: 

SELECT Last_Name
FROM employees
WHERE Last_Name LIKE '%a%' AND Last_Name LIKE '%e%';






NB: I have updated my database's some tables coloumn name.