sql：一对多【转载】

您为电话号码创建一个单独的表(即1：M关系).

create table `users` (

`id` int unsigned not null auto_increment,

`name` varchar(100) not null,

primary key(`id`)

);

create table `phone_numbers` (

`id` int unsigned not null auto_increment,

`user_id` int unsigned not null,

`phone_number` varchar(25) not null,

index pn_user_index(`user_id`),

foreign key (`user_id`) references users(`id`) on delete cascade,

primary key(`id`)

);

现在,您可以通过简单的连接轻松获取用户的电话号码;

select

pn.`phone_number`

from

`users` as u,

`phone_numbers` as pn

where

u.`name`='John'

and

pn.`user_id`=u.`id`
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原文链接：https://blog.csdn.net/weixin_29552845/article/details/113437389