; 20 RESEARCH SCOTT 20 20 RESEARCH SMITH 20 20 SALES ALLEN 30 30 SALES BLAKE 30 30 SALES JAMES 30 30 SALES MARTIN 30 30 SALES TURNER 30 30 SALES WARD 30 30 --------------------------------------------- [自连接：同一表表根据别名来访问] select a.ename A_ename,b.ename B_ename,a.mgr A_mgr,b.empno B_empno from emp a,emp b where a.mgr=b.empno order by b.ename,a.ename
A_ENAME B_ENAME A_MGR B_EMPNO ---------- ---------- --------- --------- ALLEN BLAKE 7698 7698 JAMES BLAKE 7698 7698 MARTIN BLAKE 7698 7698 TURNER BLAKE 7698 7698 WARD BLAKE 7698 7698 MILLER CLARK 7782 7782 SMITH FORD 7902 7902 FORD JONES 7566 7566 SCOTT JONES 7566 7566 BLAKE KING 7839 7839 CLARK KING 7839 7839 JONES KING 7839 7839 ADAMS SCOTT 7788 7788 ----------------------------------------- select e.deptno,e.ename from emp e where exists (select ''''x'''' from dept d where e.deptno=d.deptno and d.loc=''''NEW YORK'''') order by e.empno;
DEPTNO ENAME --------- ---------- 10 CLARK 10 KING 10 MILLER
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