mysql文章與標籤簡單查詢（FIND_IN_SET使用）

建表

DROP TABLE IF EXISTS `news`; CREATE TABLE `news` (
  `news_id` int(11) NOT NULL AUTO_INCREMENT,
  `title` varchar(100) DEFAULT NULL,
  `tags` varchar(100) DEFAULT NULL,
  PRIMARY KEY (`news_id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8; insert  into `news`(`news_id`,`title`,`tags`) values (1,'文章1','1,2'),(2,'文章2','1,2,3'),(3,'文章3','3'),(4,'文章4','1,4'); DROP TABLE IF EXISTS `tag`; CREATE TABLE `tag` (
  `t_id` int(11) NOT NULL AUTO_INCREMENT,
  `tag_name` varchar(100) DEFAULT NULL,
  PRIMARY KEY (`t_id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8; insert  into `tag`(`t_id`,`tag_name`) values (1,'標籤1'),(2,'標籤2'),(3,'標籤3'),(4,'標籤4');

 

 

====>根據標籤id,查詢文章

SELECT *
FROM news
WHERE FIND_IN_SET('2',news.tags);

 

====>查詢文章所帶的標籤

SELECT tags
FROM news
WHERE news_id=1

#代碼處理成[1,2]
SELECT *
FROM tag
WHERE t_id IN (1,2);

 

====>根據一個標籤查詢文章表所有的文章

SELECT 
    n.title,t.tag_name 
FROM news AS n 
LEFT JOIN tag AS t ON  LOCATE(CONCAT(t.t_id,','),CONCAT(n.tags,',')) 
WHERE t.tag_name='標籤2';

 

 

====>查詢標籤id爲1或者2的文章 倒序，前兩條   

SELECT *
FROM news
WHERE FIND_IN_SET('2',news.tags) OR FIND_IN_SET('1',news.tags) ORDER BY news_id DESC LIMIT 0,2;