create table emp(empno int,ename varchar(10),sal money,deptno int)
insert into emp values(1,'a',3000,10),(2,'b',4000,20),(3,'c',5000,30),(4,'d',2000,20),(5,'e',3000,null)
create table dept(deptno int,dname varchar(10),loc char(3))
insert into dept values(10,'accounts','ny'),(20,'research','hyd'),(30,'sales','hyd'),(40,'operations','hyd')
select e.ename , d.dname
from emp as e full join dept as d 
on e.deptno=d.deptno
where d.dname is null
      or
      e.ename is null
create table salgrade(grade int,losal money,hisal money)
insert into salgrade values(1,1000,2000),(2,2001,3000),(3,3001,4000),(4,4001,5000),(5,5001,10000)
select e.ename,e.sal,s.grade
from emp as e join salgrade as s
on e.sal between s.losal and s.hisal