Oracle中case when函数和decode函数

1、case when函数：

select ename,case deptno
when 10 then 'ACCOUNTING'
when 20 then 'RESEARCH'
else 'SALES' end from emp;

select ename,case
when deptno=10 then 'ACCOUNTING'
when deptno=20 then 'RESEARCH'
else 'SALES' end from emp;

以上两种写法均可。

2、decode函数：

select ename,decode(deptno,10,'ACCOUNTING',20,'RESEARCH',30,'SALES','OTHERS') from emp;