较常见的SQL面/笔试题
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比较常见的SQL面/笔试题
2014-07-25 16:18:04| 分类： 数据库 | 标签：oracle |举报|字号 订阅
1.查询每个月倒数第 2 天入职的员工的信息.
2.查询出last_name为 ‘Chen’ 的 manager 的信息.
3.查询平均工资高于 8000 的部门 id 和它的平均工资.
4. 查询工资最低的员工信息: last_name, salary
5. 查询平均工资最低的部门信息
6. 查询平均工资最低的部门信息和该部门的平均工资
7. 查询平均工资最高的 job 信息
8. 查询平均工资高于公司平均工资的部门有哪些?
9. 查询出公司中所有 manager 的详细信息.
10. 各个部门中最高工资中最低的那个部门的最低工资是多少
11. 查询平均工资最高的部门的 manager 的详细信息: last_name, department_id, email, salary
12. 查询 1999 年来公司的人所有员工的最高工资的那个员工的信息.
13.返回其它部门中比job_id为‘IT_PROG’部门所有工资都低的员工的员工号、姓名、job_id以及salary
************************answers*********************
1.查询每个月倒数第 2 天入职的员工的信息.
selectlast_name, hire_date
from employees
wherehire_date = last_day(hire_date) – 1
2.查询出last_name为 ‘Chen’ 的 manager 的信息.
1). 通过两条sql查询:
selectmanager_id
from employees
where lower(last_name) = ‘chen’ –返回的结果为 108
select *
from employees
whereemployee_id = 108
2). 通过一条sql查询(自连接):
select m.*
from employees e, employees m
wheree.manager_id = m.employee_id and e.last_name = ‘Chen’
3). 通过一条sql查询(子查询):
select *
from employees
whereemployee_id = (
selectmanager_id
from employees
wherelast_name = ‘Chen’
)
3.查询平均工资高于 8000 的部门 id 和它的平均工资.
SELECT department_id, avg(salary)
FROM employees e
GROUP BY department_id
HAVING avg(salary) > 8000
4. 查询工资最低的员工信息: last_name, salary
SELECT last_name, salary
FROM employees
WHERE salary = (
SELECT min(salary)
FROM employees
)
5. 查询平均工资最低的部门信息
SELECT *
FROM departments
WHERE department_id = (
SELECT department_id
FROM employees
GROUP BY department_id
HAVING avg(salary) = (
SELECT min(avg(salary))
FROM employees
GROUP BY department_id
)
)
6. 查询平均工资最低的部门信息和该部门的平均工资
select d.*, (select avg(salary) from employees where department_id = d.department_id)
from departments d
whered.department_id = (
SELECT department_id
FROM employees
GROUP BY department_id
HAVING avg(salary) = (
SELECT min(avg(salary))
FROM employees
GROUP BY department_id
)
)
7. 查询平均工资最高的 job 信息
1). 按job_id分组, 查询最高的平均工资
SELECT max(avg(salary))
FROM employees
GROUP BY job_id
2). 查询出平均工资等于 1) 的job_id
SELECT job_id
FROM employees
GROUP BY job_id
HAVING avg(salary) = (
SELECT max(avg(salary))
FROM employees
GROUP BY job_id
)
3). 查询出 2) 对应的 job 信息
SELECT *
FROM jobs
WHERE job_id = (
SELECT job_id
FROM employees
GROUP BY job_id
HAVING avg(salary) = (
SELECT max(avg(salary))
FROM employees
GROUP BY job_id
)
)
8. 查询平均工资高于公司平均工资的部门有哪些?
1). 查询出公司的平均工资
SELECT avg(salary)
FROM employees
2). 查询平均工资高于 1) 的部门 ID
SELECT department_id
FROM employees
GROUP BY department_id
HAVING avg(salary) > (
SELECT avg(salary)
FROM employees
)
9. 查询出公司中所有 manager 的详细信息.
1). 查询出所有的manager_id
SELECT distinct manager_id
FROM employeess
2). 查询出employee_id为 1) 查询结果的那些员工的信息
SELECT employee_id, last_name
FROM employees
WHERE employee_id in (
SELECT distinct manager_id
FROM employees
)
10. 各个部门中最高工资中最低的那个部门的最低工资是多少
1). 查询出各个部门的最高工资
SELECT max(salary)
FROM employees
GROUP BY department_id
2). 查询出 1) 对应的查询结果的最低值: 各个部门中最低的最高工资(无法查询对应的department_id)
SELECT min(max(salary))
FROM employees
GROUP BY department_id
3). 查询出 2) 所对应的部门 id 是多少: 各个部门中最高工资等于 2) 的那个部门的id
SELECT department_id
FROM employees
GROUP BY department_id
HAVING max(salary) = (
SELECT min(max(salary))
FROM employees
GROUP BY department_id
)
4). 查询出 3) 所在部门的最低工资
SELECT min(salary)
FROM employees
WHERE department_id = (
SELECT department_id
FROM employees
GROUP BY department_id
HAVING max(salary) = (
SELECT min(max(salary))
FROM employees
GROUP BY department_id
)
)
11. 查询平均工资最高的部门的 manager 的详细信息: last_name, department_id, email, salary
1). 各个部门中, 查询平均工资最高的平均工资是多少
SELECT max(avg(salary))
FROM employees
GROUP BY department_id
2). 各个部门中, 平均工资等于 1) 的那个部门的部门号是多少
SELECT department_id
FROM employees
GROUP BY department_id
HAVING avg(salary) = (
SELECT max(avg(salary))
FROM employees
GROUP BY department_id
)
3). 查询出 2) 对应的部门的manager_id
SELECT manager_id
FROM departments
WHERE department_id = (
SELECT department_id
FROM employees
GROUP BY department_id
HAVING avg(salary) = (
SELECT max(avg(salary))
FROM employees
GROUP BY department_id
)
)
4). 查询出employee_id为 3) 查询的manager_id的员工的last_name, department_id, email, salary
SELECT last_name, department_id, email, salary
FROM employees
WHERE employee_id = (
SELECT manager_id
FROM departments
WHERE department_id = (
SELECT department_id
FROM employees
GROUP BY department_id
HAVING avg(salary) = (
SELECT max(avg(salary))
FROM employees
GROUP BY department_id
)
)
)
12. 查询 1999 年来公司的人所有员工的最高工资的那个员工的信息.
1). 查询出 1999 年来公司的所有的员工的 salary
SELECT salary
FROM employees
WHERE to_char(hire_date, ‘yyyy’) = ’1999′
2). 查询出 1) 对应的结果的最大值
SELECT max(salary)
FROM employees
WHERE to_char(hire_date, ‘yyyy’) = ’1999′
3). 查询工资等于 2) 对应的结果且 1999 年入职的员工信息
SELECT *
FROM employees
WHERE to_char(hire_date, ‘yyyy’) = ’1999′ AND salary = (
SELECT max(salary)
FROM employees
WHERE to_char(hire_date, ‘yyyy’) = ’1999′
)
13.返回其它部门中比job_id为‘IT_PROG’部门所有工资都低的员工的员工号、姓名、job_id以及salary
SELECT employee_id, last_name, job_id, salary
FROM employees
WHERE salary< ALL
(SELECT salary
FROM employees
WHERE job_id = ‘IT_PROG’)
AND job_id<> ‘IT_PROG’;
******************高级子查询******************
- 书写多列子查询
- 在FROM 子句中使用子查询
- 在SQL中使用单列子查询
- 书写相关子查询
- 使用EXISTS 和NOT EXISTS 操作符
- 使用子查询更新和删除数据
- 使用WITH 子句
–多列子查询（不成对比较&成对比较）
1.查询与141号或174号员工的manager_id和department_id相同的其他员工的employee_id, manager_id, department_id
[方式一]
SELECT employee_id, manager_id, department_id
FROM employees
WHERE manager_id IN
(SELECT manager_id
FROM employees
WHERE employee_id IN (174,141))
AND department_id IN
(SELECT department_id
FROM employees
WHERE employee_id IN (174,141))
AND employee_id NOT IN(174,141);
[方式二]
SELECT employee_id, manager_id, department_id
FROM employees
WHERE (manager_id, department_id) IN
(SELECT manager_id, department_id
FROM employees
WHERE employee_id IN (141,174))
AND employee_id NOT IN (141,174);
–在 FROM 子句中使用子查询
2.返回比本部门平均工资高的员工的last_name, department_id, salary及平均工资
[方式一]
selectlast_name,department_id,salary,
(selectavg(salary)from employees e3
where e1.department_id = e3.department_id
group by department_id) avg_salary
from employees e1
where salary >
(selectavg(salary)
from employees e2
where e1.department_id = e2.department_id
–group by department_id
)
[方式二]
SELECT a.last_name, a.salary,
a.department_id, b.salavg
FROM employees a, (SELECT department_id,
AVG(salary) salavg
FROM employees
GROUP BY department_id) b
WHERE a.department_id = b.department_id
AND a.salary>b.salavg;
–单列子查询表达式
- Oracle8i只在下列情况下可以使用, 例如:
- SELECT 语句(FROM 和 WHERE 子句)
- INSERT 语句中的VALUES列表中
- Oracle9i中单列子查询表达式可在下列情况下使用:
- DECODE 和CASE
- SELECT 中除GROUP BY 子句以外的所有子句中
3.显式员工的employee_id,last_name和location。其中，若员工department_id与location_id为1800的department_id相同，则location为‘Canada’,其余则为‘USA’。
SELECT employee_id, last_name,
(CASE department_id
WHEN(SELECT department_id FROM departments
WHERE location_id = 1800)
THEN ‘Canada’ ELSE ‘USA’ END) location
FROM employees;
4.查询员工的employee_id,last_name,要求按照员工的department_name排序
SELECT employee_id, last_name
FROM employees e
ORDER BY (SELECT department_name
FROM departments d
WHERE e.department_id = d.department_id);
—相关子查询：
5.查询员工中工资大于本部门平均工资的员工的last_name,
salary和其department_id
SELECT last_name, salary, department_id
FROM employees outer
WHERE salary>
(SELECT AVG(salary)
FROM employees
WHERE department_id =
outer.department_id) ;
6.若employees表中employee_id与job_history表中employee_id相同的数目不小于2，输出这些相同id的员工的employee_id,last_name和其job_id
SELECT e.employee_id, last_name,e.job_id
FROM employees e
WHERE 2<= (SELECT COUNT(*)
FROM job_history
WHERE employee_id = e.employee_id);
–EXISTS 操作符
- EXISTS 操作符检查在子查询中是否存在满足条件的行
- 如果在子查询中存在满足条件的行:
- 不在子查询中继续查找
- 条件返回TRUE
7.查询公司管理者的employee_id,last_name,job_id,
department_id信息
SELECT employee_id, last_name, job_id, department_id
FROM employees outer
WHERE EXISTS ( SELECT ‘X’
FROM employees
WHERE manager_id =
outer.employee_id);
8.查询departments表中，不存在于employees表中的部门的department_id和department_name
SELECT department_id, department_name
FROM departments d
WHERE NOT EXISTS (SELECT ‘X’
FROM employees
WHERE department_id
= d.department_id);
–关于数据更新
9.修改表employees,添加department_name列，赋予department_id相应的部门名称。
ALTER TABLE employees
ADD(department_name VARCHAR2(14));
UPDATE employees e
SET department_name =
(SELECT department_name
FROM departments d
WHERE e.department_id = d.department_id);
–关于数据删除
10.删除表employees中，其与emp_history表皆有的数据
DELETE FROM employees E
WHERE employee_id in
(SELECT employee_id
FROM emp_history
WHERE employee_id = E.employee_id);
–WITH 子句
11.查询公司中各部门的总工资大于公司中各部门的平均总工资的部门信息
WITH
dept_costs AS (
SELECT d.department_name, SUM(e.salary) AS dept_total
FROM employees e, departments d
WHERE e.department_id = d.department_id
GROUP BY d.department_name),
avg_cost AS (
SELECT SUM(dept_total)/COUNT(*) AS dept_avg
FROM dept_costs)
SELECT *
FROM dept_costs
WHERE dept_total>
(SELECT dept_avg
FROM avg_cost)
ORDER BY department_name;
附加题目：
12.查询员工的last_name, department_id, salary.其中员工的salary,department_id与有奖金的任何一个员工的salary,
department_id相同即可
selectlast_name,department_id,salary
fromemployees
where(salary,department_id)in(
selectsalary,department_id
fromemployees
wherecommission_pctisnotnull
)
13.选择工资大于所有JOB_ID = ‘SA_MAN’的员工的工资的员工的last_name, job_id, salary
selectlast_name,job_id,salary
fromemployees
wheresalary>all(
selectsalary
fromemployees
wherejob_id=’SA_MAN’
)
14.选择所有没有管理者的员工的last_name
selectlast_name
fromemployeese1
wherenotexists(
select’A’
fromemployeese2
wheree1.manager_id=e2.employee_id
)
15.查询10，50，20号部门的job_id，department_id并且department_id按10，50，20的顺序排列
Column dummy noprint;
selectjob_id , department_id ,1 dummy
from employees
wheredepartment_id = 10
union
selectjob_id , department_id , 2
from employees
wheredepartment_id = 50
union
selectjob_id , department_id , 3
from employees
wheredepartment_id= 20
order by 3
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