PHP实现MySQL的主键id⾃动重新⾃增排序⼀.创建⼀个数据库db_idlist执⾏SQL代码
DROP TABLE IF EXISTS `tb_idlist`;
CREATE TABLE `tb_idlist` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`content` varchar(20) DEFAULT NULL,
PRIMARY KEY (`Id`)
) ENGINE=MyISAM AUTO_INCREMENT=1DEFAULT CHARSET=utf8;
⼆.新建index.php
<?php
$conn=mysqli_connect("127.0.0.1","root","123456","db_idlist") or die("数据库服务器连接错误".mysqli_error($conn));
mysqli_select_db($conn,"db_idlist") or die("数据库访问错误".mysqli_error($conn));
mysqli_query($conn,"set names utf-8");
$query = mysqli_query($conn, 'select * from tb_idlist;');
if (!$query) {
exit('<h1>查询数据失败</h1>');drop table if exists user
}
while ($item = mysqli_fetch_assoc($query));
>
<!DOCTYPE html>
<html>
<head>
<title>ID重新排序</title>
</head>
<body>
<table align="center">
<h1><a href="listid.php">排序</a></h1>
<tr>
<th scope="row"><?php echo$item['id']; ?></th>
<td><?php echo$item['content']; ?></td></tr>
</table>
</body>
</html>
三.创建listid.php
<?php
$conn=mysqli_connect("127.0.0.1","root","123456","db_idlist") or die("数据库服务器连接错误".mysqli_error($conn));
mysqli_select_db($conn,"db_idlist") or die("数据库访问错误".mysqli_error($conn));
mysqli_query($conn,"set names utf-8");
$sql = "alter table tb_idlist drop column id;";//删除原有表中的id字段
$query = mysqli_query($conn,$sql);
echo mysqli_error($conn);
if(!$query){
exit('<h1>查询数据失败</h1>');
}
$sqll = "alter table tb_idlist add id mediumint(8) not null primary key auto_increment first;";//重新设置id主键并⾃动从1开始⾃增
$query = mysqli_query($conn,$sqll);
echo mysqli_error($conn);
if(!$query){
exit('<h1>查询数据失败</h1>');
}
header('Location: index.php');
>

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