mysqli使用

<?php

////判断数据库是否连接成功

$connection = mysqli_connect('localhost', 'root', '12345678', 'ceshi', 3306 );
if ( $connection ) {
echo "数据库连接成功"."<br>";
}else {
echo "数据库连接失败"."<br>";
}
?>

<?php

////查询表中数据，并且输出

$mysqli = new MYSQLI( 'localhost', 'root', '12345678', 'ceshi', 3306 );
$query="select * from dunling_chat";
$result=$mysqli->query($query);
if ($result) {
if($result->num_rows>0){ //判断结果集中行的数目是否大于0
while($row =$result->fetch_array() ){ //循环输出结果集中的记录
echo ($row[0])."<br>";
echo ($row[1])."<br>";
echo ($row[2])."<br>";
echo ($row[3])."<br>";
echo "<hr>";
}
}
}else {
echo "查询失败";
}
$result->free();
$mysqli->close();
?>

<?php
$mysqli = new MYSQLI( 'localhost', 'root', '12345678', 'ceshi', 3306 ); //实例化mysqli
$query="select * from dunling_chat";
$result=$mysqli->prepare($query); //进行预准备语句查询
$result->execute(); //执行预准备语句
$result->bind_result($id,$nicheng,$content,$time); //绑定结果
while ($result->fetch()) {
echo $id."<br />";
echo $nicheng."<br />";
echo $content."<br />";
echo $time."<br />";
}
$result->close(); //关闭预准备语句
$mysqli->close(); //关闭连接
?>

<?php
/////插入一个数据
$mysqli = new MYSQLI( 'localhost', 'root', '12345678', 'ceshi', 3306 ); //实例化mysqli
$query="insert into dunling_chat (id,nicheng,content,time) values (?,?,?,?)";
$result=$mysqli->prepare($query);
$result->bind_param("isss",$id,$nicheng,$content,$time); //绑定参数
$id=9;
$nicheng='1234';
$content='好';
$time='2019-8-1';
$result->execute(); //执行预准备语句
$result->close();
$mysqli->close();
?>

<?php
///// 可以同时绑定参数和绑定结果
$mysqli = new MYSQLI( 'localhost', 'root', '12345678', 'ceshi', 3306 ); //实例化mysqli
$query="select * from dunling_chat where id < ?";
$result=$mysqli->prepare($query);
$result->bind_param("i",$id); //绑定参数
$id=3;
$result->execute();
$result->bind_result($id,$nicheng,$content,$time); //绑定结果
while ($result->fetch()) {
echo $id."<br>";
echo $nicheng."<br>";
echo $content."<br>";
echo $time."<br>";
}
$result->close();
$mysqli->close();
?>

<?php

////多个查询
$mysqli = new MYSQLI( 'localhost', 'root', '12345678', 'think', 3306 ); //实例化mysqli
$query = "select id from think_user ;";
$query .= "select id from think_data ";
if ($mysqli->multi_query($query)) { //执行多个查询
do {
if ($result = $mysqli->store_result()) {
while ($row = $result->fetch_row()) {
echo $row[0];
echo "<br>";
}
$result->close();
}
if ($mysqli->more_results()) {
echo ("-----------------<br>"); //连个查询之间的分割线
}
} while ($mysqli->next_result());
}
$mysqli->close();//关闭连接
?>

<?php
$id=$_GET['id'];
///// 参数 传参 可以同时绑定参数和绑定结果
$mysqli = new MYSQLI( 'localhost', 'root', '12345678', 'ceshi', 3306 ); //实例化mysqli
$query="select * from dunling_chat where id < ?";
$result=$mysqli->prepare($query);
$result->bind_param("i",$id); //绑定参数

$result->execute();
$result->bind_result($id,$nicheng,$content,$time); //绑定结果
while ($result->fetch()) {
echo $id."<br>";
echo $nicheng."<br>";
echo $content."<br>";
echo $time."<br>";
}
$result->close();
$mysqli->close();
?>