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有这样一个需求,在Mysql数据库字符串字段(权限)中,用户有多个不同的邮箱,分别被‘,’分开,现在要取出某个邮箱的所有成员列表。
假设有个表:
CREATE TABLE users(id int(6) NOT NULL AUTO_INCREMENT,PRIMARY KEY (id),user_name VARCHAR(20) NOT NULL,emails VARCHAR(50) NOT NULL);
初始化表,并添加些记录。
truncate table usersINSERT INTO users(user_name, emails) VALUES('小张','a@email.com,b@email.com,c@email.com');INSERT INTO users(user_name, emails) VALUES('小王','aa@email.com,bb@email.com,cc@email.com');
Mysql 中有些字段是字符串类型的,如何查找其中包含某些字符的记录呢?
方法一
很简单可以用%来实现
比如
SELECT * FROM users WHERE emails like "%b@email.com%";
但是这样子的话就会把bb@email.com也查出来了就不符合需求了
方法二
利用mysql 字符串函数 find_in_set();
SELECT * FROM users WHERE find_in_set('aa@email.com', emails);
这样子就可以找到email字段里包含有aa@emial.com的所有用户了
这样就能达到我们预期的效果,问题就解决了!
要注意的是:mysql字符串函数 find_in_set(str1,str2)函数是返回str2中str1所在的位置索引,str2必须以","分割开。
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