Mysql练习题（多表子查询）

SQL练习题（多表子查询）

–创建员工信息表
TABLE emp(
empno INT,–员工编号
ename VARCHAR(50),–员工姓名
job VARCHAR(50),–员工职位
mgr INT,–上级编号
hiredate DATE,–受雇日期
sal DECIMAL(7,2),–薪水
comm DECIMAL(7,2),–佣金
deptno INT–部门编号
) ;
–添加数据
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);
INSERT INTO emp VALUES(7981,‘MILLER’,‘CLERK’,7788,‘1992-01-23’,2600,500,20);

–创建部门表
CREATE TABLE dept(
deptno INT,–部门编号
dname VARCHAR(14), –部门名称
loc VARCHAR(13) –地方
);
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’);

– 单行子查询(> < >= <= = <>)
– 查询出高于10号部门的平均工资的员工信息
SELECT AVG(sal) FROM emp WHERE deptno=10 –10号部门的平均工资
SELECT * FROM emp WHERE sal >(SELECT AVG(sal) FROM emp WHERE deptno=10 );

– 多行子查询(in not in any all)
– 查询出比10号部门任何员工薪资高的员工信息
SELECT sal FROM emp WHERE deptno=10 –查询十号部门员工的工薪
SELECT * FROM emp WHERE sal > ANY(SELECT sal FROM emp WHERE deptno=10) AND deptno!=10;

– 多列子查询(实际使用较少)
– 和10号部门同名同工作的员工信息
SELECT ename,job FROM emp WHERE deptno=10 –查询十号部门所有员工的工作和名字
SELECT * FROM emp WHERE (ename,job)IN(SELECT ename,job FROM emp WHERE deptno=10) AND deptno!=10;

– select 后面接子查询
– 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
– 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
– 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
– 有哪些部门的平均工资高于30号部门的平均工资
SELECT deptno, AVG(sal) AS bumen FROM emp GROUP BY deptno HAVING bumen > (SELECT AVG(sal) FROM emp WHERE deptno=30);
– 工资>JONES工资

SELECT * FROM emp WHERE sal>(SELECT sal FROM emp WHERE ename=‘JONES’);
– 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’;
– 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);
– 查询工作和工资与MARTIN完全相同的员工信息
SELECT job,sal FROM emp WHERE ename=‘MARTIN’;
SELECT * FROM emp WHERE (job,sal)IN(SELECT job,sal FROM emp WHERE ename=‘MARTIN’);
– 有两个以上直接下属的员工信息
– 得出两个以上的经理信息
SELECT mgr,COUNT(mgr) FROM emp GROUP BY mgr HAVING COUNT() >2;
– 得出两个以上直接下属的员工信息
SELECT * FROM emp WHERE empno IN (SELECT mgr FROM emp GROUP BY mgr HAVING COUNT(mgr) >2);
– 老师的方法
SELECT * FROM emp e1 WHERE e1.empno IN (SELECT e2.mgr FROM emp e2 GROUP BY e2.mgr HAVING COUNT()>2);

– 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;
– 1. 查询出高于本部门平均工资的员工信息-
SELECT *,AVG(sal) AS 平均工资 FROM emp GROUP BY deptno;
SELECT * FROM emp e WHERE sal > (SELECT AVG(sal) AS 平均工资 FROM emp d GROUP BY deptno HAVING e.deptno=d.deptno);
– 方式二:
– SELECT * FROM emp e1 WHERE e1.sal > (SELECT AVG(e2.sal) FROM emp e2 WHERE e1.deptno=e2.deptno GROUP BY e2.deptno);
– 列出达拉斯加工作的人中,比纽约平均工资高的人
SELECT AVG(sal) FROM emp e INNER JOIN dept d ON e.deptno=d.deptno WHERE d.loc=‘NEW YORK’;

SELECT * FROM emp e INNER JOIN dept d ON e.deptno=d.deptno WHERE d.loc=‘DALLAS’
AND sal>(SELECT AVG(sal) FROM emp e INNER JOIN dept d ON e.deptno=d.deptno WHERE d.loc=‘NEW YORK’);
– 方法二
SELECT * FROM emp WHERE deptno = (SELECT deptno FROM dept WHERE loc=‘DALLAS’)
AND sal > (SELECT AVG(sal) FROM emp WHERE deptno = (SELECT deptno FROM dept WHERE loc=‘NEW YORK’));
– 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);

SELECT empno,ename,(SELECT mgr FROM emp WHERE empno=7369) AS 经理编号
,(SELECT ename FROM emp WHERE empno =(SELECT mgr FROM emp WHERE empno=7369)) AS 经理姓名 FROM emp WHERE empno=7369;

SELECT e1.empno,e1.ename,e1.mgr,mgrtable.ename FROM emp e1,emp mgrtable WHERE e1.mgr = mgrtable.empno AND e1.empno=7369;
– 查询出各个部门薪水最高的员工所有信息
SELECT * FROM emp WHERE sal=MAX(sal) GROUP BY deptno;

SELECT * FROM emp e WHERE sal = (SELECT MAX(sal) AS 最高薪水 FROM emp e2 WHERE e.deptno=e2.deptno GROUP BY deptno );

– SELECT * FROM emp e1 WHERE e1.sal = (SELECT MAX(sal) FROM emp e2 WHERE e1.deptno = e2.deptno GROUP BY deptno);

–面试题
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);

– 请用一条Sql语句查处分数大于80的学生
SELECT DISTINCT NAME FROM test WHERE fenshu>80;