题干：

-- 子查询
CREATE TABLE emp(
    empno        INT,
    ename        VARCHAR(50),
    job        VARCHAR(50),
    mgr        INT,
    hiredate    DATE,
    sal        DECIMAL(7,2),
    comm        DECIMAL(7,2),
    deptno        INT
) ;

INSERT INTO emp VALUES(7369,'SMITH','CLERK',7902,'1980-12-17',800,NULL,20);
INSERT INTO emp VALUES(7499,'ALLEN','SALESMAN',7698,'1981-02-20',1600,300,30);
INSERT INTO emp VALUES(7521,'WARD','SALESMAN',7698,'1981-02-22',1250,500,30);
INSERT INTO emp VALUES(7566,'JONES','MANAGER',7839,'1981-04-02',2975,NULL,20);
INSERT INTO emp VALUES(7654,'MARTIN','SALESMAN',7698,'1981-09-28',1250,1400,30);
INSERT INTO emp VALUES(7698,'BLAKE','MANAGER',7839,'1981-05-01',2850,NULL,30);
INSERT INTO emp VALUES(7782,'CLARK','MANAGER',7839,'1981-06-09',2450,NULL,10);
INSERT INTO emp VALUES(7788,'SCOTT','ANALYST',7566,'1987-04-19',3000,NULL,20);
INSERT INTO emp VALUES(7839,'KING','PRESIDENT',NULL,'1981-11-17',5000,NULL,10);
INSERT INTO emp VALUES(7844,'TURNER','SALESMAN',7698,'1981-09-08',1500,0,30);
INSERT INTO emp VALUES(7876,'ADAMS','CLERK',7788,'1987-05-23',1100,NULL,20);
INSERT INTO emp VALUES(7900,'JAMES','CLERK',7698,'1981-12-03',950,NULL,30);
INSERT INTO emp VALUES(7902,'FORD','ANALYST',7566,'1981-12-03',3000,NULL,20);
INSERT INTO emp VALUES(7934,'MILLER','CLERK',7782,'1982-01-23',1300,NULL,10);

select * from emp;

CREATE TABLE dept(
    deptno        INT,
    dname        VARCHAR(14),
    loc        VARCHAR(13)
);

INSERT INTO dept VALUES(10, 'ACCOUNTING', 'NEW YORK');
INSERT INTO dept VALUES(20, 'RESEARCH', 'DALLAS');
INSERT INTO dept VALUES(30, 'SALES', 'CHICAGO');
INSERT INTO dept VALUES(40, 'OPERATIONS', 'BOSTON');

select * from dept;

要求：

-- 单行子查询(> < >= <= = <>)
-- 1.查询出高于10号部门的平均工资的员工信息

select empno, ename, sal from emp where sal > (select avg(sal) from  emp where deptno = 10);

---

-- 多行子查询(in  not in any all)
-- 2.查询出比10号部门任息何员工薪资高的员工信息
select *from emp where sal > any (select  sal from  emp where  deptno = 10);

---

-- 多列子查询(实际使用较少)
-- 3.和10号部门同名同工作的员工信息

SELECT * FROM emp WHERE (enameob)IN(SELECT ename,job FROM emp WHERE deptno=10) AND deptno!=1；

---

 -- select 后面接子查询    
-- 4.获取员工的名字和部门的名字
select p.ename,d.dname from emp p,dept d where p.deptno=d.deptno;

---

 -- from 后面接子查询
-- 5.查询emp表中经理信息
select * from  emp e,(select distinct mgr from emp) as jingli where e.empno=jingli.mgr;

---

 -- where 后面接子查询    
-- 6.薪资高于10号部门平均工资的所有员工信息
select * from emp where sal>(select avg(sal) from  emp where deptno=10);    

---

 -- group by 后面接子查询
-- 7.有哪些部门的平均工资高于30号部门的平均工资

---

 -- 8.工资>JONES工资
select* from emp where sal>(select sal from emp where ename='JONES');

---

 -- 9.查询与SCOTT同一个部门的员工
select * from emp where deptno = (select deptno from emp where ename='SCOTT') and ename!='SCOTT';

---

-- 10.工资高于30号部门所有人的员工信息
select * from emp where sal>(select max(sal) from emp where deptno=30);

---

-- 11.查询工作和工资与MARTIN完全相同的员工信息

---

-- 12.有两个以上直接下属的员工信息

---

-- 13.查询员工编号为7788的员工名称,员工工资,部门名称,部门地址
select e.* ,d.loc from emp e,dept d where e.empno=7788 and e.deptno=d.deptno;

---

-- SQL查询的综合案例
-- 14.查询出高于本部门平均工资的员工信息

---

-- 15.列出达拉斯加工作的人中,比纽约平均工资高的人

---

-- 16.查询7369员工编号,姓名,经理编号和经理姓名
select  mgr from emp where empno=7369;
select ename from emp where empno =(select mgr from emp where empno=7369);

---

-- 17.查询出各个部门薪水最高的员工所有信息

---

题干：

CREATE TABLE test(
NAME CHAR(20),
kecheng CHAR(20),
fenshu CHAR(20)
);

INSERT INTO test VALUES('张三','语文',81),
('张三','数学',75),
('李四','语文',76),
('李四','数学',90),
('王五','语文',81),
('王五','数学',82);

select * from test；

 

-- 18.请用一条Sql语句查处分数大于80的学生
select * from test where fenshu > 80;