黑猴子的家：mysql 连接查询（非等值查询）

1、非等值连接案例一

案例：查询员工的工资以及对应的工资级别

SELECT salary,grade_level
FROM employees e,job_grades g
WHERE e.`salary` BETWEEN g.`lowest_sal` AND g.`highest_sal`;

2、非等值连接案例二

案例：查询名字中第三个字符为a，第五个字符为e的员工的工资以及对应的工资级别

SELECT salary,grade_level
FROM employees e,job_grades g
WHERE e.`salary` BETWEEN g.`lowest_sal` AND g.`highest_sal`
AND e.`last_name` LIKE '__a_e%';

3、数据补给

SELECT * FROM employees;

SELECT * FROM job_grades;
CREATE TABLE job_grades
(grade_level VARCHAR(3),
 lowest_sal  INT,
 highest_sal INT);

INSERT INTO job_grades
VALUES ('A', 1000, 2999);

INSERT INTO job_grades
VALUES ('B', 3000, 5999);

INSERT INTO job_grades
VALUES('C', 6000, 9999);

INSERT INTO job_grades
VALUES('D', 10000, 14999);

INSERT INTO job_grades
VALUES('E', 15000, 24999);

INSERT INTO job_grades
VALUES('F', 25000, 40000);