How to connect php to mysql and query data

How to implement PHP to connect to mysql and query data: first use the mysqli_connect function to establish a connection with the database; then use the mysqli_query function combined with the select statement to query the database data.

Uncomment extension=php.mysqli_dll in php.ini.

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Code example:

<?php
 
//php连接需要用到mysqli函数 而它是一个扩展
//在php.ini中 解除注释extension=php.mysqli_dll 即可
 
//与数据库建立连接
//主机地址 数据库用户名 密码 数据库名称
 $connection=  mysqli_connect(&#39;127.0.0.1&#39;,&#39;root&#39;,&#39;123456&#39;,&#39;demo&#39;);
 
 
 if(!$connection){
	 //连接失败
	 exit(&#39;<h1>数据库连接失败</h1>&#39;);
 }
 //基于刚创建的连接对象进行一次查询操作
 $query= mysqli_query($connection,&#39;select * from users&#39;);
  
  if(!$query){
	  exit(&#39;<h1>查询失败</h1>&#39;);
  }
 //遍历结果集
 while ($row=mysqli_fetch_assoc($query)){
	 //打印结果集
	 var_dump($row);
 }
  //释放结果集
  mysqli_free_result($query);
  //断开与数据库连接
  mysqli_close($connection);
?>

Table data queried by Navicat in the database

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