内连接:
select emp.empno,emp.ename,dept.dname from emp inner join dept on emp.deptno=dept.deptno;
select emp.empno,emp.ename,dept.dname from emp,dept emp.deptno=dept.deptno; :左边表完全显示,右边表不完全显示select * from dept left join emp on emp.deptno=dept.deptno;
select * from dept , emp where emp.deptno(+)=dept.deptno;
右外连接:右边表完全显示,左边表不完全显示 select * from dept right join emp on emp.deptno=dept.deptno; select * from dept,emp where emp.deptno=dept.deptno(+);
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