使用分析函数进行行列转换

SQL> SELECT deptno, ename,
2         ROW_NUMBER () OVER (PARTITION BY deptno ORDER BY sal DESC) seq
3    FROM emp;
DEPTNO ENAME             SEQ
---------- ---------- ----------
10 KING                1
10 CLARK               2
10 MILLER              3
20 SCOTT               1
20 FORD                2
20 JONES               3
20 ADAMS               4
20 SMITH               5
30 BLAKE               1
30 ALLEN               2
30 TURNER              3
30 WARD                4
30 MARTIN              5
30 JAMES               6
14 rows selected.

SQL> select deptno,
2  max(decode(seq,1,ename,null)) highest,
3  max(decode(seq,2,ename,null)) second,
4  max(decode(seq,3,ename,null)) third
5  from (
6  select deptno,ename,
7  row_number() over
8  (partition by deptno order by sal desc) seq
9  from emp)
10  where seq <=3 group by deptno
11  /
DEPTNO HIGHEST    SECOND     THIRD
---------- ---------- ---------- ----------
10 KING       CLARK      MILLER
20 SCOTT      FORD       JONES
30 BLAKE      ALLEN      TURNER