-- 谁的工资比Abel高？
select last_name, salary from employees where salary>(select salary from employees where last_name = 'Abel');
LAST_NAME SALARY ------------------------- ---------- King 24000 Kochhar 17000 De Haan 17000 Hartstein 13000
--查询员工为Chen的manager的信息（Chen对应一个manager_id）
select last_name,salary from employees where employee_id = (select manager_id from employees where last_name = 'Chen');
LAST_NAME SALARY ------------------------- ---------- Greenberg 12000
-- 返回job_id与141号员工相同，salary比143号员工多的员工姓名，job_id和工资
select last_name, job_id,salary from employees where job_id = (select job_id from employees where employee_id=141) and salary >(select salary from employees where employee_id = 143);
LAST_NAME JOB_ID SALARY ------------------------- ---------- ---------- Rajs ST_CLERK 3500 Davies ST_CLERK 3100 Nayer ST_CLERK 3200 Mikkilineni ST_CLERK 2700
-- 查询最低工资大于50号部门的最低工资的部门id和其最低工资
select department_id,min(salary) from employees group by department_id having min(salary)>(select min(salary) from employees where department_id = 50);
DEPARTMENT_ID MIN(SALARY) ------------- ----------- 7000 100 6900 30 2500
-- 多行子查询
--返回其他部门中比job_id为IT_PROG部门任一工资低的员工的员工号，姓名，job_id, salary
select employee_id,last_name,job_id,salary from employees where job_id <> 'IT_PROG' AND salary < any (select salary from employees where job_id = 'IT_PROG');
EMPLOYEE_ID LAST_NAME JOB_ID SALARY ----------- ------------------------- ---------- ---------- 132 Olson ST_CLERK 2100 128 Markle ST_CLERK 2200 136 Philtanker ST_CLERK 2200
子查询中的空值 空值了不会报错 空了就空了
练习：
--1.查询平均工资最低的部门信息
select * from departments where department_id = (select department_id from employees having avg(salary) = (select min(avg(salary)) from employees group by department_id ) group by department_id);
DEPARTMENT_ID DEPARTMENT_NAME MANAGER_ID LOCATION_ID ------------- ------------------------------ ---------- ----------- 50 Shipping 124 1500
2.从 jobs 表中返回 job_id 的对应项的信息
select * from jobs where job_id in( select job_id from employees having avg(salary) = ( select max(avg(salary)) from employees group by job_id ) group by job_id
JOB_ID JOB_TITLE MIN_SALARY MAX_SALARY ---------- ----------------------------------- ---------- ---------- AD_PRES President 20000 40000
--3.查询平均工资高于公司平均工资的部门有哪些
select department_id,avg(salary) from employees group by department_id having avg(salary)>( select avg(salary) from employees )order by department_id asc;
DEPARTMENT_ID AVG(SALARY) ------------- ----------- 20 9500 40 6500 70 10000 80 8955.882353
-- 4.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
select min(salary) from employees where department_id = (select department_id from employees having max(salary) = (select min(max(salary)) from employees group by department_id) group by department_id ); --各个部门最高工资最低的那个部门工资, 通过那个部门最高的工资 找到department_id，用到分组了最高得group by一下 select department_id from employees having max(salary) = (select min(max(salary)) from employees group by department_id) group by department_id; --各个部门最高工资最低的那个部门工资 select min(max(salary)) from employees group by department_id;
MIN(SALARY) ----------- 4400
-- 5.查询1999年来公司的员工中最高工资的那个员工的信息
select * from employees where salary = ( select max(salary) from employees where to_char(hire_date,'yyyy') = '1999' ) and to_char(hire_date,'yyyy') = '1999';
EMPLOYEE_ID FIRST_NAME LAST_NAME EMAIL PHONE_NUMBER HIRE_DATE JOB_ID SALARY COMMISSION_PCT MANAGER_ID DEPARTMENT_ID ----------- -------------------- ------------------------- ------------------------- -------------------- --------- ---------- ---------- -------------- ---------- ------------- 148 Gerald Cambrault GCAMBRAU 011.44.1344.619268 15-10月-99 SA_MAN 11000 0.3 100 80
-- 6.查询和Zlotkey相同部门的员工姓名和雇用日期
select last_name,hire_date from employees where department_id = ( select department_id from employees where last_name = 'Zlotkey' ) and last_name <> 'Zlotkey'
LAST_NAME HIRE_DATE ------------------------- --------- Abel 11-5月 -96 Taylor 24-3月 -98
--7.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 last_name,employee_id,salary from employees where salary > ( select avg(salary) from employees);
LAST_NAME EMPLOYEE_ID SALARY ------------------------- ----------- ---------- King 100 24000 Kochhar 101 17000
-- 8.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， 两个salary都是同一个部门 得建立关系
select employee_id,last_name,salary from employees e1 where salary > ( select avg(salary) from employees e2 where e1.department_id = e2.department_id group by department_id );
EMPLOYEE_ID LAST_NAME SALARY ----------- ------------------------- ---------- 100 King 24000 103 Hunold 9000
--9.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 in ( select department_id from employees where last_name like '%u%' ) and last_name not like '%u%';
EMPLOYEE_ID LAST_NAME ----------- ------------------------- 106 Pataballa 107 Lorentz
--10.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 );
EMPLOYEE_ID ----------- 100 101 102
--11.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' )
LAST_NAME SALARY ------------------------- ---------- Kochhar 17000 De Haan 17000