[分享]闫志东，多表查询

2024-04-16 15:04:45

183

SELECT e.employee_id,d.department_name

FROM employees AS e,departments AS d

WHERE e.department_id = d.department_id(+);

-- sql99

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

FROM employees AS e

INNER JOIN departments AS d ON e.department_id = d.department_id

INNER JOIN locations AS l ON l.location_id = d.location_id;

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

FROM employees AS e

RIGHT OUTER JOIN departments AS d ON e.department_id = d.department_id

-- RIGHT OUTER JOIN locations AS l ON l.location_id = d.location_id;