php 连接mysql

@屏蔽错误信息，error_reporting(0),也是屏蔽错误信息

连接数据库时，如有有错就报错误信息

$m=@new mysqli('localhost','rootr','','db');
$m->set_charset('utf8');
if($m->connect_error){
	echo $m->connect_error;
	exit;
}
$m->close();//关闭数据库连接

不提示警告错误error_reporting(0);

连接数据库

$conn = mysql_connect('localhost','root','');

设置连接数据库的编码字符集为utf8

mysql_query('set names utf8',$conn);

选择数据库

mysql_select_db('db',$conn);

执行创建数sql据库语句

创建数据库

mysql_query('create database db',$conn);

删除数据库

mysql_query('drop database if exists db',$conn);

插入一条信息

$t = time();

$ip = $_SERVER['REMOTE_ADDR'];

$sql = "insert into guest values(null,'张三','公司位置?','公司在哪里，电话是多少',$t,'$ip')";

给数据库发送一条执行指令

mysql_query($sql,$conn);

关闭数据库连接

mysql_close($conn);

删除数据

$m->query('delete from stu where id in(1,2,3)');

$m->close();

预处理语句删除数据 

$stmt=$m->prepare('delete from stu where id in(?,?)');

$id1=12;

$id2=4;

$stmt->bind_param('ii',$id1,$id2);/ii表示2个整数

$stmt->execute();

$stmt->close();

修改数据 

$m->query("update stu set name=='李四'where id=2");

预处理语句修改数据

$stmt=$m->prepare('update stu set name=? where id =?');

$stmt->bind_param('si',$name,$id);

$name='张三';

$id=11;

$stmt->execute();

使用预处理语句查询

$stmt=$m->prepare('slect * from sta');

$stmt->execute;

$result=$stmt->get_result();

while($rs=$result->fetch_row(){

print_r($rs);

}

$stmt->free_result();

mysql_list_dbs();列出数据库

mysql_get_client_info()取得mysql的客户端信息

mysql_get_host_info()取得主机信息

mysql_get_proto_info()取得协议信息

mysql_get_server_info()取得服务器信息

mysql_result($result,2,1)表示查询的第二行第1列位置的数据显示结果为赵六

查询数据库里面的信息有几条

 $conn=@mysql_connect('localhost','root','');
 mysql_query('set names utf8',$conn);
 mysql_select_db('db',$conn);
$result=mysql_query('select count(*) from guest',$conn);
echo mysql_result($result,0);
 mysql_close($conn);

1

查询显示姓名时间

 $conn=@mysql_connect('localhost','root','');
 mysql_query('set names utf8',$conn);
 mysql_select_db('db',$conn);
$result=mysql_query('select gname,gtime from guest');
if($rs=mysql_fetch_row($result)){
	echo '姓名:'.$rs[0].'时间:'.date('Y-m-d H:i:s',$rs[1]).'<br>';
}
 mysql_close($conn);

 $conn=@mysql_connect('localhost','root','');
 mysql_query('set names utf8',$conn);
 mysql_select_db('db',$conn);
$result=mysql_query('select gname,gtime from guest');
echo '<pre>';
if($rs=mysql_fetch_row($result)){
	print_r($rs);
}
 mysql_close($conn);

mysql_fetch_assoc($result)显示关联下标名称

 $conn=@mysql_connect('localhost','root','');
 mysql_query('set names utf8',$conn);
 mysql_select_db('db',$conn);
$result=mysql_query('select gname,gtime from guest');
echo '<pre>';
if($rs=mysql_fetch_assoc($result)){
	print_r($rs);
}
 mysql_close($conn);

mysql_fetch_array($result)打印输出关联下标及名称，打印两遍浪费内存

 $conn=@mysql_connect('localhost','root','');
 mysql_query('set names utf8',$conn);
 mysql_select_db('db',$conn);
$result=mysql_query('select gname,gtime from guest');
echo '<pre>';
if($rs=mysql_fetch_array($result)){
	print_r($rs);
}
 mysql_close($conn);

mysql_free_result($result);释放内存

=unset($result);

echo mysql_num_fields($result);查询有多少列信息

echo mysql_affected_rows();显示上一次的mysql操作影响了几行可以用来判断是否执行正确

mysqli创建数据库删除数据库

 $conn=mysqli_connect('localhost','root','','db',3306);
 //创建数据库
 //mysqli_query($conn,'create database da2');
 //如果存在删除数据库
 $stmt=mysqli_prepare($conn,'drop database if exists da2');
 mysqli_execute($stmt);
 mysqli_close($conn);

使用预处理语句，查询数据库信息

$m=new mysqli('localhost','root','','db');
$m->set_charset('utf8');
$r=$m->query('select user from mysql.user');
while($rs=$r->fetch_row()){
	print_r($rs);
}
$r->free();//释放查询结果$r所占用的内存
$m->close();//关闭数据库连接

$m->select_db('mysql');//切换当前连接指定的数据库

$r=$m->query('select user from user');//从数据库中查询信息

if($rs=$r->fetch_row()){

    print_r($rs);

}

mysql 释放内存

mysql_free_result（$result）;

使用预处理语句实现数据的插入

$m=new mysqli('localhost','root','','db');
$m->set_charset('utf8');
//使用预处理语句，实现数据插入
$n='张三丰';
$stmt=$m->prepare('insert into stu values(null,?)');
$stmt->bind_param('s',$n);
$stmt->execute();
$stmt->free_result();
//释放查询结果$r所占用的内存
$m->close();//关闭数据库连接

预处理查询语句，一定要用while语句，使用if只会显示一条信息

$m=new mysqli('localhost','root','','db');
$m->set_charset('utf8');
$result=$m->query('select * from stu');
echo '<pre>';
while($rs=$result->fetch_row()){
	print_r($rs);
}
$m->close();//关闭数据库连接

删除数据

$m=new mysqli('localhost','root','','db');
$m->set_charset('utf8');
$m->query('delete from stu where sid in(1,2)');
$m->close();//关闭数据库连接

使用预处理删除数据

bind_param('ii',$id1,$id2);

ii表示后面跟了2个变量，也可用s,d 

$m=new mysqli('localhost','root','','db');
$m->set_charset('utf8');
$stmt=$m->prepare('delete from stu where sid in (?,?)');
$id1=3;
$id2=4;
$stmt->bind_param('ii',$id1,$id2);
$stmt->execute();
$m->close();//关闭数据库连接

修改数据

$host = 'localhost';
$user = 'root';
$pass = '';
$dbname = 'db';
$charset = 'utf8';
$m = new mysqli($host,$user,$pass,$dbname);
$m->set_charset($charset);
$m->query("update stu set sname='李四' where sid=7");

用预处理语句修改数据信息

<?php
$host = 'localhost';
$user = 'root';
$pass = '';
$dbname = 'db';
$charset = 'utf8';
$m = new mysqli($host,$user,$pass,$dbname);
$m->set_charset($charset);
$stmt=$m->prepare('update stu set sname=? where sid=?');
$stmt->bind_param('ss',$name,$id);
$name='赵六六';
$id=7;
$stmt->execute();

<?php
$m=new mysqli('localhost','root','','db');
if($m->connect_error){
	exit('数据库连接失败请检查....');
}
if($stmt=$m->prepare('select count(*) from member where maccount=?')){
	
	$stmt->bind_param('s',$account);
	$account='222';
	$stmt->execute();
	$stmt->bind_result($count);
	$stmt->fetch();
	$stmt->free_result();
	$stmt->close();
	echo '结果是：'.$count;
}
$m->close();
//返回结果1表明有这个用户名

<?php
$m=new mysqli('localhost','root','','db');
$m->set_charset('utf8');//指定字符集
if($m->connect_error){
	exit('数据库连接失败请检查....');
}
if($stmt=$m->prepare('select * from member')){
	$stmt->execute();
	$result=$stmt->get_result();
	$rows=$result->fetch_all(MYSQLI_NUM);
	echo '<pre>';
	print_r($rows);
}

fetch_all(MYSQLI_NUM)=2

fetch_all(MYSQLI_ASSOC)=1

fetch_all(MYSQLI_BOTH)=3

echo MYSQLI_NUM,MYSQLI_ASSOC,MYSQL_BOTH;

来自为知笔记(Wiz)