sql 99 数据库连接

--交叉连接
select * from emp e cross join dept d;

--自然连接
select * from emp e natural join dept d;

--指定字段
select * from emp join dept using(deptno);

--内连接
select * from emp e join dept d on e.deptno = d.deptno;
select * from emp e inner join dept d on e.deptno = d.deptno;

左外连接
select * from emp e left join dept d on e.deptno = d.deptno;
select * from emp e left outer join dept d on e.deptno = d.deptno;

右外连接
select * from emp e right outer join dept d on e.deptno = d.deptno;

全外连接
select * from emp e full outer join dept d on e.deptno = d.deptno;