#案例：查询员工的工资级别SELECT salary,grade_levelFROM employees eJOIN job_grades gON e.`salary` BETWEEN g.`lowest_sal
#案例：查询员工的工资级别
SELECT salary,grade_levelFROM employees eJOIN job_grades gON 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_levelFROM job_grades jJOIN employees eON 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_nameFROM employees eINNER JOIN departments dON 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_titleFROM employees eINNER JOIN jobs jON e.job_id=j.job_idWHERE e.last_name LIKE ‘%e%';以上就是本次介绍的全部知识点内容。
