mysql_多表子查询

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);INSERT INTO emp VALUES(7981,\'MILLER\',\'CLERK\',7788,\'1992-01-23\',2600,500,20);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\');-- 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 * 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 * FROM emp WHERE sal > ANY(SELECT sal FROM emp WHERE deptno=10) AND deptno!=10;-- 多列子查询-- 和10号部门同名同工作的员工信息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);-- 第二种方法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;