Oracle ->> 行转列， 列转行

除了Pivot和Unpivot这两个函数，还有像CASE WHEN + 聚合函数像MAX,SUM这类的来完成。今天发现Oracle下居然有这样一个和SQL SERVER 2012以后新增的新函数叫IIF相似功能的函数叫decode

SELECT  *
  FROM  (SELECT job,
                sum(decode(deptno,10,sal)) DEPT10,
                sum(decode(deptno,20,sal)) DEPT20,
                sum(decode(deptno,30,sal)) DEPT30,
                sum(decode(deptno,40,sal)) DEPT40
           FROM scott.emp
       GROUP BY job)
ORDER BY 1;
JOB           DEPT10     DEPT20     DEPT30     DEPT40
--------- ---------- ---------- ---------- ----------
ANALYST                    6000
CLERK           1300       1900        950
MANAGER         2450       2975       2850
PRESIDENT       5000
SALESMAN                              5600