某廢柴的廢棄日記

今天Database Lab,對着一條這樣棘手的題目,我敗了 orz

Find all pairs of employees who have the same monthly salary. For each pair of them, list their numbers, names, and salaries. Note that each pair should only be listed once

出來的結果卻只能做成這樣...

SQL> SELECT DISTINCT e.empno,e.ename,e.sal,se.empno,se.ename,se.sal FROM EMP e, EMP se
  2  WHERE e.sal = se.sal
  3  AND NOT e.empno=se.empno;

     EMPNO ENAME             SAL      EMPNO ENAME             SAL
---------- ---------- ---------- ---------- ---------- ----------
      7654 MARTIN           1250       7521 WARD             1250
      7521 WARD             1250       7654 MARTIN           1250
      7902 FORD             3000       7788 SCOTT            3000
      7788 SCOTT            3000       7902 FORD             3000

SQL>

面對這應該如此卻出不到的結果......

     EMPNO ENAME             SAL      EMPNO ENAME             SAL
---------- ---------- ---------- ---------- ---------- ----------
      7654 MARTIN           1250       7521 WARD             1250
      7902 FORD             3000       7788 SCOTT            3000

我真的敗給祢了 orz

標籤： Software