mysql练习题3

USE day44;

-- 1 查出所有员工的名字，薪资,格式为
--     <名字:egon>    <薪资:3000>
SELECT '姓名：',name,'薪资：',salary from employee;

-- 2 查出所有的岗位（去掉重复）
select distinct(post) from employee;

-- 3 查出所有员工名字，以及他们的年薪,年薪的字段名为annual_year
SELECT name,salary*12 as annual_year from employee;




-- 1. 查看岗位是teacher的员工姓名、年龄
select name,age from employee where post='teacher';

-- 2. 查看岗位是teacher且年龄大于30岁的员工姓名、年龄
select name,age from employee where post='teacher' and age>30;

-- 3. 查看岗位是teacher且薪资在9000-1000范围内的员工姓名、年龄、薪资
select name,age,salary from employee 
 			where post='teacher' and salary BETWEEN 9000 and 10000;

-- 4. 查看岗位描述不为NULL的员工信息
select * from employee where not null;

-- 5. 查看岗位是teacher且薪资是10000或9000或30000的员工姓名、年龄、薪资
select * from employee where post='teacher' and salary in (10000,9000,30000);

-- 6. 查看岗位是teacher且薪资不是10000或9000或30000的员工姓名、年龄、薪资
select * from employee where post='teacher' and salary not in(10000,9000,30000);

-- 7. 查看岗位是teacher且名字是jin开头的员工姓名、年薪
select * from employee where name like 'jin%';



-- 1. 查询岗位名以及岗位包含的所有员工名字
select post,group_concat(name) from employee group by post;

-- 2. 查询岗位名以及各岗位内包含的员工个数
select post,count(id) from employee group by post;

-- 3. 查询公司内男员工和女员工的个数
select sex,count(id) from employee group by sex;

-- 4. 查询岗位名以及各岗位的平均薪资
select post,avg(salary) from employee group by post;

-- 5. 查询岗位名以及各岗位的最高薪资
select post,max(salary) from employee GROUP BY post;

-- 6. 查询岗位名以及各岗位的最低薪资
select post,min(salary) from employee GROUP BY post;

-- 7. 查询男员工与男员工的平均薪资，女员工与女员工的平均薪资
select sex,avg(salary) from employee group by sex;




-- 1. 查询各岗位内包含的员工个数小于2的岗位名、岗位内包含员工名字、个数
select post,group_concat(name),count(id) from employee group by post having count(id)<2;

-- 3. 查询各岗位平均薪资大于10000的岗位名、平均工资
select post,avg(salary) from employee group by post having avg(salary)>10000;

-- 4. 查询各岗位平均薪资大于10000且小于20000的岗位名、平均工资
SELECT post,avg(salary) from employee group by post 
				having avg(salary)>10000 and avg(salary)<20000;



-- 1. 查询所有员工信息，先按照age升序排序，如果age相同则按照hire_date降序排序
select * from employee order by age asc,hire_date desc;

-- 2. 查询各岗位平均薪资大于10000的岗位名、平均工资,结果按平均薪资升序排列
select post,avg(salary)as a from employee group by post 
				having avg(salary)>10000 order by a asc;

-- 3. 查询各岗位平均薪资大于10000的岗位名、平均工资,结果按平均薪资降序排列
select post,avg(salary) a from employee group by post 
						having avg(salary) >10000 order by a desc;




-- 查看所有员工中名字是jin开头，n或者g结果的员工信息
select * from employee where name REGEXP '^jin.*[n|g]$';