MySQL查询以获取用户未加入的所有社区
我想获得用户尚未加入的所有社区(基于不同的ZIP) 我有一个用户表和其他几个类似的表:MySQL查询以获取用户未加入的所有社区,mysql,Mysql,我想获得用户尚未加入的所有社区(基于不同的ZIP) 我有一个用户表和其他几个类似的表: select * from neighborhood where neighborhood_id NOT IN (select neighborhood_id from user_neighborhood where user_id != 1) AND neighborhood_postal_code IN ('2000', '2100') 表名:邻里 CREATE TABLE neighborhood(
select *
from neighborhood
where neighborhood_id NOT IN (select neighborhood_id from user_neighborhood where user_id != 1)
AND neighborhood_postal_code IN ('2000', '2100')
表名:邻里
CREATE TABLE neighborhood(
`neighborhood_id` INT(11) NOT NULL AUTO_INCREMENT,
`name` VARCHAR(255) NOT NULL,
`description` TEXT DEFAULT NULL,
`neighborhood_postal_code` VARCHAR(255) NOT NULL,
`region_neighborhood` VARCHAR(255) NOT NULL,
`created_at` DATETIME DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`neighborhood_id`),
INDEX `neighborhood_region_neighborhood_FI_1` (`region_neighborhood`)
) ENGINE = InnoDB;
CREATE TABLE user_neighborhood(
`user_id` INT(11) NOT NULL,
`neighborhood_id` INT(11) NOT NULL,
`activity_circle` INT(1) DEFAULT 0,
`duo_circle` INT(1) DEFAULT 0,
FOREIGN KEY (`user_id`) REFERENCES `users` (`user_id`),
FOREIGN KEY (`neighborhood_id`) REFERENCES `neighborhood` (`neighborhood_id`)
) ENGINE = InnoDB;
表名:user\u邻域
CREATE TABLE neighborhood(
`neighborhood_id` INT(11) NOT NULL AUTO_INCREMENT,
`name` VARCHAR(255) NOT NULL,
`description` TEXT DEFAULT NULL,
`neighborhood_postal_code` VARCHAR(255) NOT NULL,
`region_neighborhood` VARCHAR(255) NOT NULL,
`created_at` DATETIME DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`neighborhood_id`),
INDEX `neighborhood_region_neighborhood_FI_1` (`region_neighborhood`)
) ENGINE = InnoDB;
CREATE TABLE user_neighborhood(
`user_id` INT(11) NOT NULL,
`neighborhood_id` INT(11) NOT NULL,
`activity_circle` INT(1) DEFAULT 0,
`duo_circle` INT(1) DEFAULT 0,
FOREIGN KEY (`user_id`) REFERENCES `users` (`user_id`),
FOREIGN KEY (`neighborhood_id`) REFERENCES `neighborhood` (`neighborhood_id`)
) ENGINE = InnoDB;
我尝试了以下查询,但结果不正确:
SELECT n.*
FROM `neighborhood` as n
left join user_neighborhood as un on n.neighborhood_id = un.neighborhood_id
where un.user_id != 1 and n.neighborhood_postal_code IN ('2000', '2100')
更新:我第一次使用如下子查询设法使查询看起来正确:
select *
from neighborhood
where neighborhood_id NOT IN (select neighborhood_id from user_neighborhood where user_id != 1)
AND neighborhood_postal_code IN ('2000', '2100')
然而,它也返回(一些)我已经在的社区。我不太明白为什么只有一些 你到底为什么要添加用户id!=子查询中的1?我认为,如果您知道要获取的用户的id(假设user_id为10),则在子查询中使用where user_id=10,如:
select *
from neighborhood
where neighborhood_id NOT IN (select distinct neighborhood_id from user_neighborhood where user_id = 10)
AND neighborhood_postal_code IN ('2000', '2100')
但如果要获取所有没有用户的邻居,则可以使用以下查询:
select *
from neighborhood
where neighborhood_id NOT IN (select distinct neighborhood_id from user_neighborhood)
AND neighborhood_postal_code IN ('2000', '2100')
希望这有帮助 这是可行的,它完全有道理,它必须在id=而不是!=。。为了这个,我伤了头太久了。谢谢