Question

我有以下问题。

人们在网站上发布任务。

人们发布的所有任务都按照以下结构进入任务表：

id
user_id
date_posted

并且有一个包含下表的用户表

id
first_name
email

我需要收到超过一周未发布任务的人的电子邮件吗？我怎样才能做到这一点？我尝试了以下方法：

SELECT distinct u.id, u.email FROM user as u WHERE id IN (SELECT user_id FROM task WHERE paid = 1 AND DATE_ADD(CURDATE(), INTERVAL -7 DAY) <= `date_posted` AND `date_posted` < DATE_ADD(CURDATE(), INTERVAL -6 DAY)) AND role = 0

但我不认为这是正确的方法。我该怎么办？

Answer 1

尝试此查询

SELECT u.id, u.email 
FROM user as u WHERE id NOT IN ( /* select users who posted */
  SELECT distinct user_id FROM task 
  WHERE paid = 1 AND DATE_SUB(CURDATE(), INTERVAL 7 DAY) <= `date_posted` 
) AND role = 0;

未经测试，但您明白了。

Answer 2

试试这个

SELECT DISTINCT u.id, u.email
FROM (
        SELECT t.user_id AS user_id
        FROM task t
        WHERE DATE(t.date_posted) > DATE_SUB(CURDATE(), INTERVAL 7 DAY)
    ) AS t
RIGHT JOIN USER u ON u.id = t.user_id
WHERE t.user_id IS NULL

收到超过1周未发布的人的电子邮件

2 个答案: