子查询-练习题

1. 查询和Zlotkey相同部门的员工姓名和工资
2. 查询工资比公司平均工资高的员工的员工号，姓名和工资。
3. 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
4. 查询和姓名中包含字母u的员工在相同部门的员工的员工号和姓名
5. 查询在部门的location_id为1700的部门工作的员工的员工号
6. 查询管理者是King的员工姓名和工资
7. 查询工资最低的员工信息: last_name, salary
8. 查询平均工资最低的部门信息
9. 查询平均工资最低的部门信息和该部门的平均工资（相关子查询）
10. 查询平均工资最高的 job 信息
11. 查询平均工资高于公司平均工资的部门有哪些?
12. 查询出公司中所有 manager 的详细信息
13. 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?
14. 查询平均工资最高的部门的 manager 的详细信息: last_name, department_id, email, salary
15. 查询部门的部门号，其中不包括job_id是"ST_CLERK"的部门号
16. 选择所有没有管理者的员工的last_name
17. 查询员工号、姓名、雇用时间、工资，其中员工的管理者为 ‘De Haan’
18. 查询各部门中工资比本部门平均工资高的员工的员工号, 姓名和工资（相关子查询）
19. 查询每个部门下的部门人数大于 5 的部门名称（相关子查询）
20. 查询每个国家下的部门个数大于 2 的国家编号（相关子查询）

1.查询和Zlotkey相同部门的员工姓名和工资
SELECT last_name, salary
FROM employees
WHERE department_id = (
SELECT department_id
FROM employees
WHERE last_name = 'Zlotkey'
)
2.查询工资比公司平均工资高的员工的员工号，姓名和工资
SELECT employee_id, last_name, salary
FROM employees
WHERE salary > (
SELECT AVG(salary)
FROM employees
)
3.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
SELECT last_name,job_id,salary
FROM employees
WHERE salary > ALL (
SELECT salary
FROM employees
WHERE job_id = 'SA_MAN'
);
4.查询和姓名中包含字母u的员工在相同部门的员工的员工号和姓名
SELECT employee_id, last_name
FROM employees
WHERE department_id = ANY(
SELECT DISTINCT department_id
FROM employees
WHERE last_name LIKE '%u%'
)
5.查询在部门的location_id为1700的部门工作的员工的员工号
SELECT employee_id
FROM employees
WHERE department_id IN (
SELECT department_id
FROM departments
WHERE location_id = 1700
)
6.查询管理者是King的员工姓名和工资
SELECT last_name, salary
FROM employees
WHERE manager_id IN (
SELECT employee_id
FROM employees
WHERE last_name = 'King'
)
7.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
);
8.查询平均工资最低的部门信息
#方式一：
SELECT *
FROM departments
WHERE department_id = (
SELECT department_id
FROM employees
GROUP BY department_id
HAVING AVG(salary) = (
SELECT MIN(dept_avgsal)
FROM (
SELECT AVG(salary) dept_avgsal
FROM employees
GROUP BY department_id
) avg_sal
)
);
#方式二：
SELECT *
FROM departments
WHERE department_id = (
SELECT department_id
FROM employees
GROUP BY department_id
HAVING AVG(salary) <= ALL(
SELECT AVG(salary) avg_sal
FROM employees
GROUP BY department_id
)
);
#方式三：
SELECT *
FROM departments
WHERE department_id = (SELECT department_id
FROM employees
GROUP BY department_id
HAVING AVG(salary) = (
SELECT AVG(salary) avg_sal
FROM employees
GROUP BY department_id
ORDER BY avg_sal
LIMIT 0,1
)
);
#方式四：
SELECT d.*
FROM departments d,(
SELECT department_id,AVG(salary) avg_sal
FROM employees
GROUP BY department_id
ORDER BY avg_sal
LIMIT 0,1) dept_avg_sal
WHERE d.department_id = dept_avg_sal.department_id
9.查询平均工资最低的部门信息和该部门的平均工资（相关子查询）
SELECT d.*,(SELECT AVG(salary) FROM employees WHERE department_id = d.department_id)
avg_sal
FROM departments d
WHERE department_id = (
SELECT department_id
FROM employees
GROUP BY department_id
HAVING AVG(salary) = (
SELECT MIN(dept_avgsal)
FROM (
SELECT AVG(salary) dept_avgsal
FROM employees
GROUP BY department_id
) avg_sal
)
);
#方式二：
SELECT d.*,(SELECT AVG(salary) FROM employees WHERE department_id = d.`department_id`)
avg_sal
FROM departments d
WHERE department_id = (
SELECT department_id
FROM employees
GROUP BY department_id
HAVING AVG(salary) <= ALL(
SELECT AVG(salary) avg_sal
FROM employees
GROUP BY department_id
)
);
#方式三：
SELECT d.*,(SELECT AVG(salary) FROM employees WHERE department_id = d.department_id)
avg_sal
FROM departments d
WHERE department_id = (
SELECT department_id
FROM employees
GROUP BY department_id
HAVING AVG(salary) = (
SELECT AVG(salary) avg_sal
FROM employees
GROUP BY department_id
ORDER BY avg_sal
LIMIT 0,1
)
);
#方式四：
SELECT d.*,dept_avg_sal.avg_sal
FROM departments d,(
SELECT department_id,AVG(salary) avg_sal
FROM employees
GROUP BY department_id
ORDER BY avg_sal
LIMIT 0,1) dept_avg_sal
WHERE d.department_id = dept_avg_sal.department_id
10.查询平均工资最高的 job 信息
#方式一：
SELECT *
FROM jobs
WHERE job_id = (
SELECT job_id
FROM employees
GROUP BY job_id
HAVING AVG(salary) = (
SELECT MAX(avg_sal)
FROM(
SELECT AVG(salary) avg_sal
FROM employees
GROUP BY job_id
) job_avgsal
)
);
#方式二：
SELECT *
FROM jobs
WHERE job_id = (
SELECT job_id
FROM employees
GROUP BY job_id
HAVING AVG(salary) >= ALL(
SELECT AVG(salary)
FROM employees
GROUP BY job_id
)
);
#方式三：
SELECT *
FROM jobs
WHERE job_id = (
SELECT job_id
FROM employees
GROUP BY job_id
HAVING AVG(salary) = (
SELECT AVG(salary) avg_sal
FROM employees
GROUP BY job_id
ORDER BY avg_sal DESC
LIMIT 0,1
)
);
#方式四：
SELECT j.*
FROM jobs j,(
SELECT job_id,AVG(salary) avg_sal
FROM employees
GROUP BY job_id
ORDER BY avg_sal DESC
LIMIT 0,1 ) job_avg_sal
WHERE j.job_id = job_avg_sal.job_id
11.查询平均工资高于公司平均工资的部门有哪些?
SELECT department_id
FROM employees
WHERE department_id IS NOT NULL
GROUP BY department_id
HAVING AVG(salary) > (
SELECT AVG(salary)
FROM employees
);
12.查询出公司中所有 manager 的详细信息
#方式1：
SELECT employee_id,last_name,salary
FROM employees
WHERE employee_id IN (
SELECT DISTINCT manager_id
FROM employees
);
#方式2：
SELECT DISTINCT e1.employee_id, e1.last_name, e1.salary
FROM employees e1 JOIN employees e2
WHERE e1.employee_id = e2.manager_id;
#方式3：
SELECT employee_id, last_name, salary
FROM employees e1
WHERE EXISTS ( SELECT *
FROM employees e2
WHERE e2.manager_id = e1.employee_id);
13.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?
#方式1:
SELECT MIN(salary)
FROM employees
WHERE department_id = (
SELECT department_id
FROM employees
GROUP BY department_id
HAVING MAX(salary) = (
SELECT MIN(max_sal)
FROM (
SELECT MAX(salary) max_sal
FROM employees
GROUP BY department_id) dept_max_sal
)
);
#方式2:
SELECT MIN(salary)
FROM employees
WHERE department_id = (
SELECT department_id
FROM employees
GROUP BY department_id
HAVING MAX(salary) <= ALL(
SELECT MAX(salary) max_sal
FROM employees
GROUP BY department_id
)
);
#方式3：
SELECT MIN(salary)
FROM employees
WHERE department_id = (
SELECT department_id
FROM employees
GROUP BY department_id
HAVING MAX(salary) = (
SELECT MAX(salary) max_sal
FROM employees
GROUP BY department_id
ORDER BY max_sal
LIMIT 0,1
)
);
#方式4：
SELECT employee_id,MIN(salary)
FROM employees e,
(SELECT department_id,MAX(salary) max_sal
FROM employees
GROUP BY department_id
ORDER BY max_sal
LIMIT 0,1) dept_max_sal
WHERE e.department_id = dept_max_sal.department_id;
14. 查询平均工资最高的部门的 manager 的详细信息: last_name,
department_id, email, salary
#方式一：
SELECT employee_id,last_name, department_id, email, salary
FROM employees
WHERE employee_id IN (
SELECT DISTINCT manager_id
FROM employees
WHERE department_id = (
SELECT department_id
FROM employees
GROUP BY department_id
HAVING AVG(salary) = (
SELECT MAX(avg_sal)
FROM(
15. 查询部门的部门号，其中不包括job_id是"ST_CLERK"的部门号
SELECT AVG(salary) avg_sal
FROM employees
GROUP BY department_id
) dept_sal
)
)
);
#方式二：
SELECT employee_id,last_name, department_id, email, salary
FROM employees
WHERE employee_id IN (
SELECT DISTINCT manager_id
FROM employees
WHERE department_id = (
SELECT department_id
FROM employees e
GROUP BY department_id
HAVING AVG(salary)>=ALL(
SELECT AVG(salary)
FROM employees
GROUP BY department_id
)
)
);
#方式三：
SELECT *
FROM employees
WHERE employee_id IN (
SELECT DISTINCT manager_id
FROM employees e,(
SELECT department_id,AVG(salary) avg_sal
FROM employees
GROUP BY department_id
ORDER BY avg_sal DESC
LIMIT 0,1) dept_avg_sal
WHERE e.department_id = dept_avg_sal.department_id
);
15.查询部门的部门号，其中不包括job_id是"ST_CLERK"的部门号
#方法一：
SELECT department_id
FROM departments d
WHERE department_id NOT IN (
SELECT DISTINCT department_id
FROM employees
WHERE job_id = 'ST_CLERK'
);
#方法二：
SELECT department_id
FROM departments d
WHERE NOT EXISTS (
SELECT *
FROM employees e
WHERE d.`department_id` = e.`department_id`
AND job_id = 'ST_CLERK'
);
16.选择所有没有管理者的员工的last_name
SELECT last_name
FROM employees e1
WHERE NOT EXISTS (
SELECT *
FROM employees e2
WHERE e1.manager_id = e2.employee_id
);
17．查询员工号、姓名、雇用时间、工资，其中员工的管理者为 'De Haan'
#方式1：
SELECT employee_id, last_name, hire_date, salary
FROM employees
WHERE manager_id = (
SELECT employee_id
FROM employees
WHERE last_name = 'De Haan'
);
#方式2：
SELECT employee_id, last_name, hire_date, salary
FROM employees e1
WHERE EXISTS (
SELECT *
FROM employees e2
WHERE e2.`employee_id` = e1.manager_id
AND e2.last_name = 'De Haan'
);
18.查询各部门中工资比本部门平均工资高的员工的员工号, 姓名和工资(难)
#方式一：相关子查询
SELECT employee_id,last_name,salary
FROM employees e1
WHERE salary > (
# 查询某员工所在部门的平均
SELECT AVG(salary)
FROM employees e2
WHERE e2.department_id = e1.`department_id`
);
#方式二：
SELECT employee_id,last_name,salary
FROM employees e1,
(SELECT department_id,AVG(salary) avg_sal
FROM employees e2 GROUP BY department_id
) dept_avg_sal
WHERE e1.`department_id` = dept_avg_sal.department_id
AND e1.`salary` > dept_avg_sal.avg_sal;
19.查询每个部门下的部门人数大于 5 的部门名称
SELECT department_name,department_id
FROM departments d
WHERE 5 < (
SELECT COUNT(*)
FROM employees e
WHERE d.`department_id` = e.`department_id`
);
20.查询每个国家下的部门个数大于 2 的国家编号
SELECT country_id
FROM locations l
WHERE 2 < (
SELECT COUNT(*)
FROM departments d
WHERE l.`location_id` = d.`location_id`
);