1. 查询工资大于12000的员工姓名和工资
select initcap(concat(last_name,first_name)) "姓名",
salary "工资" from employees where salary>12000;
2. 查询员工号为176的员工的姓名和部门号
select initcap(concat(last_name,first_name)) "姓名",
department_id "部门号" from employees where employee_id=176;
3. 选择工资不在5000到12000的员工的姓名和工资
select initcap(concat(last_name,first_name)) "姓名",
salary "工资" from employees where salary not between
5000 and 12000;
4. 选择雇用时间在1998-02-01到1998-05-01之间的员工姓名，job_id和雇用时间
select initcap(concat(last_name,first_name)) "姓名",
job_id,hire_date from employees where hire_date between
to_date('1998-02-01','YYYY-MM-DD') and to_date('1998-05-01','YYYY-MM-DD');
5. 选择在20或50号部门工作的员工姓名和部门号
select initcap(concat(last_name,first_name)) "姓名",
department_id from employees where department_id in (20,50);
6. 选择在1994年雇用的员工的姓名和雇用时间
select initcap(concat(last_name,first_name)) "姓名",
hire_date from employees where
hire_date between to_date('1994-1-1','YYYY-MM-DD') and to_date('1994-12-31','YYYY-MM-DD');
7. 选择公司中没有管理者的员工姓名及job_id
select initcap(concat(last_name,first_name)) "姓名",
job_id from employees where nvl(manager_id,0)=0;
8. 选择公司中有奖金的员工姓名，工资和奖金级别
select initcap(concat(last_name,first_name)) "姓名",
job_id from employees where nvl(manager_id,0)=0;
9. 选择员工姓名的第三个字母是a的员工姓名
select initcap(concat(last_name,first_name)) "姓名",
From emloyees
Where last_name like '__a%';
10. 选择姓名中有字母a和e的员工姓名
select initcap(concat(last_name,first_name)) "姓名",
From emloyees
Where concat(last_name,first_name) like '%a%' and concat(last_name,first_name) like '%e%';
11. 显示系统时间
Select current_timestamp from dual;
12. 查询员工号，姓名，工资，以及工资提高百分之20%后的结果（new salary）
Select first_name,salary*0.2,employee_id from employees;
13. 将员工的姓名按首字母排序，并写出姓名的长度（length）
Select frist_name,length(first_name) from employees order by substr(first_name,1,1);
14. 查询各员工的姓名，并显示出各员工在公司工作的月份数
//为什么会出小数？
Select initcap(concat(last_name,first_name)) "姓名",months_between(sysdate,hire_date)
"工作月数" From employees;
15. 查询员工的姓名，以及在公司工作的月份数（worked_month），并按月份数降序排列
Select initcap(concat(last_name,first_name)) "姓名",months_between(sysdate,hire_date)
"工作月数" From employees order by months_between(sysdate,hire_date) desc;
1. 做一个查询，产生下面的结果
<last_name> earns <salary> monthly but wants <salary*3>
|
Dream Salary |
|
King earns $24000 monthly but wants $72000 |
Select last_name||' earns '||to_char(salary,'$99999')||' monthly but wants '||to_char(salary*3,'$99999') as "Dream Salary" from employees;
2. 使用decode函数，按照下面的条件：
job grade
AD_PRES A
ST_MAN B
IT_PROG C
SA_REP D
ST_CLERK E
Others F
产生下面的结果
Select last_name,job_id,decode(job_id,
'AD_PRES','A',
'ST_MAN','B',
'IT_PROG','C',
'SA_REP','D',
'ST_CLERK','E',
'F'
) as "grade" from employees;
|
Last_name |
Job_id |
Grade |
|
king |
AD_PRES |
A |
3. 将第17题的查询用case函数再写一遍。
Select last_name,job_id,
case job_id
when 'AD_PRES' then 'A'
when 'ST_MAN' then 'B'
when 'IT_PROG' then 'C'
when 'SA_REP' then 'D'
when 'ST_CLERK' then 'E'
Else 'F' end "Grage" from employees;
下面的后边学过之后写：
4. 查询公司员工工资的最大值，最小值，平均值，总和
Select max(salary) "最大值",min(salary) "最小值",avg(salary) "平均值",sum(salary) "总和" from employees;
5. 查询各job_id的员工工资的最大值，最小值，平均值，总和
Select max(salary) "最大值",min(salary) "最小值",avg(salary) "平均值",sum(salary) "总和" from employees group by job_id;
6. 选择具有各个job_id的员工人数
Select count(*),job_id from employees group by job_id;
7. 查询员工最高工资和最低工资的差距（DIFFERENCE）
Select max(salary)-min(salary) as "DIFFERENCE" from employees;
8. 查询各个管理者手下员工的最低工资，其中最低工资不能低于6000，没有管理者的员工不计算在内
Select min(salary) from employees group by manager_id having min(salary)>=6000 and manager_id is not null;
9. 查询所有部门的名字，location_id，员工数量和工资平均值
Select department_name,location_id,count(e.job_id),avg(e.salary) from departments d,employees e where d.department_id=e.department_id group by department_name,location
