#案例：查询员工的工资级别
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SELECT
salary,grade_level
FROM
employees e
JOIN
job_grades g
ON
e.`salary` BETWEEN g.`lowest_sal` AND g.`lowest_sal`;
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#案例：查询每个工资级别的个数，并且按级别降序
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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;
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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
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SELECT last_name,department_name
FROM employees e
INNER JOIN departments d
ON e.department_id=d.department_id;
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案例2:查询名字中包含e的员工名和工种名(添加筛选)
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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%';
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以上就是本次介绍的全部知识点内容。
原文链接：https://blog.51cto.com/14437184/2437910