3. Sort

1. Check all employee information , Sort by salary from low to high

select * from emp
order by sal;

2. Inquiry Department 10 Of employees , Sort by salary from high to low , If the wages are the same , Sort by employment time from early to late

select * from emp
where deptno=10 
order by sal desc,hiredate;

3. Check employee number 、 full name 、 Annual salary , Sort by annual salary from high to low

select empno,ename,(sal+ifnull(comm,0)*12 income)
from emp
order by income desc;