MySQL查询条件为

Question

我有两张桌子： users和users_img。

我需要创建一个查询，以便从users表中选择所有用户zip列不为空并且img列中的users_images列为空（两个表都有用户） ID：users。id和users_img。user_id因此可以加入这些内容。

users

1. ID
2. 名称
3. 拉链
4. 时间：LAST_TIMEBREAK

users_ids

1. ID
2. user_id（与id中的users相同）
3. IMG

我试过了：

SELECT * FROM `users` JOIN `users_ids` on users.id = users_ids.user_id
 WHERE `zip` != '' AND `img` = '' ORDER BY `last_time` DESC 

没有运气。我知道应该很简单。

Answer 1

我修改了您的查询以检查Null

中的OR值

试试这个：

SELECT * FROM `users` 
LEFT JOIN `users_ids` on users.id = users_ids.user_id 
WHERE   (TRIM(`zip`) != '' OR `zip` is not null)  AND 
(TRIM(`img`) = '' OR `img` is null) ORDER BY `last_time` DESC 

Answer 2

它也适合你

SELECT * FROM `users` as `u` 
JOIN `users_ids` as `uid` on `u`.`id` = `uid`.`user_id` 
WHERE `u`.`zip` IS NOT NULL 
AND `uid`.`img` IS NULL 
ORDER BY `u`.`last_time` DESC

Answer 3

这有效：

SELECT * FROM `users` as `u` 
LEFT JOIN `users_ids` as `uid` on `u`.`id` = `uid`.`user_id` 
WHERE `u`.`zip` != '' 
AND `uid`.`img` IS NOT NULL 
ORDER BY `u`.`last_time` DESC