emp_no	salary	from_date	to_date
10001	88958	1986-06-26	9999-01-01
10003	43311	2001-12-01	9999-01-01
10004	74057	1995-12-01	9999-01-01
10006	43311	2001-08-02	9999-01-01
10007	88070	2002-02-07	9999-01-01

请你统计出各个title类型对应的员工薪水对应的平均工资avg。结果给出title以及平均工资avg，并且以avg升序排序，以上例子输出如下:

示例1

输入:

drop table if exists  `salaries` ; 
drop table if exists  titles;
CREATE TABLE `salaries` (
`emp_no` int(11) NOT NULL,
`salary` int(11) NOT NULL,
`from_date` date NOT NULL,
`to_date` date NOT NULL,
PRIMARY KEY (`emp_no`,`from_date`));
CREATE TABLE titles (
`emp_no` int(11) NOT NULL,
`title` varchar(50) NOT NULL,
`from_date` date NOT NULL,
`to_date` date DEFAULT NULL);
INSERT INTO salaries VALUES(10001,88958,'1986-06-26','9999-01-01');
INSERT INTO salaries VALUES(10003,43311,'2001-12-01','9999-01-01');
INSERT INTO salaries VALUES(10004,74057,'1995-12-01','9999-01-01');
INSERT INTO salaries VALUES(10006,43311,'2001-08-02','9999-01-01');
INSERT INTO salaries VALUES(10007,88070,'2002-02-07','9999-01-01');

INSERT INTO titles VALUES(10001,'Senior Engineer','1986-06-26','9999-01-01');
INSERT INTO titles VALUES(10003,'Senior Engineer','2001-12-01','9999-01-01');
INSERT INTO titles VALUES(10004,'Senior Engineer','1995-12-01','9999-01-01');
INSERT INTO titles VALUES(10006,'Senior Engineer','2001-08-02','9999-01-01');
INSERT INTO titles VALUES(10007,'Senior Staff','1996-02-11','9999-01-01');

输出:

Senior Engineer|62409.2500
Senior Staff|88070.0000

原站题解

SELECT 
    t.title, 
    AVG(salary) AS 'avg(s.salary)'
FROM titles AS t 
INNER JOIN salaries AS s 
ON t.emp_no = s.emp_no
GROUP BY t.title
ORDER BY AVG(salary);

select EMP.title,avg(SA.salary) from
titles EMP join salaries SA on
EMP.emp_no = SA.emp_no 
group by EMP.title 
order by avg(SA.salary)

select t.title,avg(s.salary) a from titles t inner join salaries s 
on t.emp_no = s.emp_no group by t.title order by a asc

select t.title, avg(s.salary) from titles t join salaries s on t.emp_no = s.emp_no group by t.title order by avg(s.salary)

select title ,avg(s.salary) from titles t inner join salaries s on t.emp_no = s.emp_no group by t.title order by avg(s.salary) asc