📅  最后修改于: 2022-03-11 15:05:27.260000             🧑  作者: Mango
UPDATE employees
SET hire_date = (SELECT departments.start_date
FROM departments
WHERE departments.department_id = employees.department_id
AND departments.department_name = 'HR')
WHERE EXISTS (SELECT *
FROM departments
WHERE departments.department_id = employees.department_id
AND departments.department_name ='HR');