oracle数据库sql语句之join实例讲解

--group by

select deptno,count(*) from emp group by deptno;

--group by ... having

select deptno, count(*) from emp group by deptno having count(*)>=5;

--join

select * from emp join dept on emp.deptno = dept.deptno;

--join right

select * from emp right join dept on emp.deptno = dept.deptno;