[打卡]sql-多表查询

SELECT e.employee_id,e.last_name,d.department_name,l.city

FROM employees e,departments d,locations l

WHERE e.department_id=d.department_id AND

d.location_id=l.location_id; 

SELECT * FROM job_grades;

#举例：查询名字、月薪对应的等级

SELECT last_name,salary,grade_level

FROM employees,job_grades

WHERE employees.salary BETWEEN job_grades.lowest_sal 

AND job_grades.highest_sal;

SELECT * FROM employees;

SELECT last_name,salary,grade_level

FROM employees,job_grades

WHERE employees.salary >= job_grades.lowest_sal 

AND employees.salary <= job_grades.highest_sal;

SELECT emp.employee_id,emp.last_name,mgr.employee_id,mgr.last_name

FROM employees emp,employees mgr

WHERE emp.manager_id=mgr.employee_id;