mysql sql99语法内连接非等值连接详解

#案例：查询员工的工资级别

									SELECT

									  salary,grade_level

									FROM

									  employees e

									JOIN

									  job_grades g

									ON

									  e.`salary` BETWEEN g.`lowest_sal` AND g.`lowest_sal`;

#案例：查询每个工资级别的个数，并且按级别降序

									SELECT

									  COUNT(*),grade_level

									FROM

									  job_grades j

									JOIN

									  employees e

									ON

									  e.`salary` BETWEEN j.`lowest_sal`AND j.`highest_sal`

									GROUP BY

									  grade_level DESC;

内容扩展：

语法

select 查询列表

from 表1 别名 [连接类型]

jion 表2 别名

on 连接条件

[where 筛选条件]

[group by 分组]

[having 筛选条件]

[order by 排序列表]

案例1:查询员工名,部门名

									SELECT last_name,department_name

									FROM employees e

									INNER JOIN departments d

									ON e.department_id=d.department_id;

案例2:查询名字中包含e的员工名和工种名(添加筛选)

									SELECT last_name,job_title

									FROM employees e

									INNER JOIN jobs j

									ON e.job_id=j.job_id

									WHERE e.last_name LIKE ‘%e%';