每日一练（20171020）

一、Java编程题题目：一球从100米高度自由落下，每次落地后反跳回原高度的一半；再落下，求它在第10次落地时，共经过多少米？第10次反弹多高？答：public static double f(int n ) {if (1 == n) {return 100;} else {return f(n - 1) / 2;}}public static double t(int n ) {double d = 100.0;for(int j =2 ;j<=n;j++) {d +=f(j)*2;}return d;}System.out.println(f(10));System.out.println(t(9));二、JavaScript编程题查找字符串"sdddrtkjsfkkkasjdddj"中出现次数最多的字符和次数。var str= "sdddrtkjsfkkkasjdddj";var count = 0;var max = "";for(var j = 0 ;j<=26;j++){var tempcount = 0;var string = String.fromCharCode(97+j);for(var i = 0 ; i<str.length; i++){ var  n = str.indexof("string",i); if(n==0){ tempcount+=1; } if(tempcount>count){ count = tempcount; max = string; }}}console.log("出现最多字母:"+max+"次数："+count);三、SQL编程题员工表emp：员工编号eid，姓名ename，工作职位title，雇佣日期hiretime，工资salary，奖金bonus，部门 depart部门表dept：部门编号did，名称dname，部门领导leader员工数据： 1001,’张三’,’销售’,’1999-12-1’,3000.0,1100.0,’102’ 1002,’李四’,’研发员’,’1998-2-11’,3500.0,null,’101’ 1003,’王五’,’研发员’,’2001-1-15’,4000.0,null,’101’ 1004,’赵六’,’美工’,’2001-12-1’,4000.0,null,’101’ 1005,’武六奇’,’研发员’,’2001-7-1’,5500.0,null,’101’ 1006,’齐八九’,’销售’,’2001-6-16’,3000.0,1500.0,’102’ 1007,’钱多多’,’经理’,’2009-11-10’,6500.0,2000.0,’102’ 1008,’张一一’,’销售’,’2007-12-10’,3800.0,1000.0,’102’ 1009,’李丽丽’,’研发员’,’1999-8-19’,4500.0,null,’101’ 1010,’王旺旺’,’销售’,’1999-9-1’,3600.0,1600.0,’102’ 1011,’赵有才’,’经理’,’1999-4-30’,7000.0,1800.0,’101’ 1012,’李雷’,’出纳’,’2007-10-10’,5000.0,500.0,’103’ 1013,’韩梅’,’会计’,’2005-3-1’,6600.0,1000.0,’103’ 1014,’张向阳’,’经理’,’2002-6-1’,7000.0,1500.0,’103’ 1015,’李向东’,’销售’,’2004-5-1’,4300.0,1000.0,’102’部门数据: ‘101’,’研发部’,1007 ‘102’,’销售部’,1011 ‘103’,’财务部’,10141、查询员工姓名及所做工作SELECT ename,title FROM emp2、查询员工姓名及年薪SELECT ename,salary*12  FROM emp3、查询工资大于4000的员工信息SELECT * FROM emp WHERE salary>40004、查询年薪大于20000的员工信息SELECT * FROM emp WHERE salary*12>200005、查询没有奖金的员工SELECT*FROM emp WHERE bonus is NULL6、查询工资大于3000同时有奖金的员工信息SELECT * FROM emp WHERE salary>3000 AND  bonus  is not NULL7、查询工资大于3500但是小于5000的员工信息SELECT * FROM emp WHERE salary>3000 AND salary<50008、查询编号是1001、1003、1004的员工信息SELECT *FROM emp where eid in(1001,1003,1004)9、查询编号不是1001、1003、1004的员工信息SELECT *FROM emp where eid not in(1001,1003,1004)10、查询员工姓名是3个字的员工信息SELECT * from  emp WHERE LENGTH(ename)>=911、查询姓张的员工信息SELECT * from emp WHERE ename LIKE '张%'12、查询出员工工资没有包含6和8的员工信息SELECT *from emp WHERE salary NOT LIKE '%6%'and salary NOT LIKE'%8%'13、按照工资由高到低查询员工信息SELECT*FROM emp ORDER BY salary desc14、要求查询出101部门的所有雇员信息，查询的信息按照工资由高到低排序，如果工资相等，则按照雇佣日期由早到晚排序。SELECT *FROM emp ORDER BY salary DESC,hiretime ASC15、查询101部门有多少员工，每月平均发多少工资SELECT COUNT(ename),AVG(salary)FROM emp WHERE depart = 10116、查询101部门的所有员工信息，并显示所在部门名称SELECT eid, ename, title, hiretime, salary, bonus, depart ,dname from emp LEFT JOIN deptON emp.depart=dept.didWHERE depart=10117、查询1001员工的部门领导信息SELECT *from emp LEFT JOIN  deptON emp.depart=dept.didwhere eid =(SELECT leader from emp LEFT JOIN  deptON emp.depart=dept.did )WHERE eid = 1001)18、查询部门员工数量，平均工资，最低工资及最低工资的员工姓名SELECT COUNT(ename),AVG(salary),MIN(salary),ename FROM emp GROUP BY depart