sql题练习2
1. 找出收取佣金的员工的不同工作. select job from emp where comm is notnull 2. 找出不收取佣金或收取的佣金低于100的员工. select job from emp where comm is nullor comm<100 3. 找出各月倒数第3天受雇的所有员工. select * from emp wherehiredate=to_date(to_char(add_months(hiredate,1),'yyyy-mm'),'yyyy-mm')-3; 4. 找出早于12年前受雇的员工. select * from emp where extract(year fromsysdate)-extract(year from hiredate)>12 5. 以首字母大写的方式显示所有员工的姓名. select initcap(ename) from emp