PHP，单项查询及多项查询

先封装对象
class DBDA
{
    public $host = "localhost";    //数据库地址
    public $uid = "root";    //数据库用户名
    public $pwd = "123";    //数据库密码
    
    //执行SQL语句,返回相应的结果的方法
    //参数：$sql代表要执行的SQL语句,$type是SQL语句类型0代表查询1代表其他,$db代表要操作的数据库
    public function Query($sql,$type=0,$db="mydb")
    {
        //1.造连接对象
        $dbconnect = new MySQLi($this->host,$this->uid,$this->pwd,$db);
        //2.判断连接是否出错
        !mysqli_connect_error() or die("连接失败！");
        //3.执行SQL语句
        $result = $dbconnect->query($sql);
        
        if($type==0)
        {
            return $result->fetch_all();
        }
        else
        {
            return $result;
        }
    }
}

单项查询页面

<h1>汽车查询页面</h1>
<br />
<?php

    include("./DBDA.class.php");
   $db = new DBDA();
    
   $cx="";
    $value="";
    if(!empty($_POST["name"]))
    {
        $name = $_POST["name"];
        $cx = " where Name like ‘%{$name}%‘";//查询字符串
        $value = $name;
    }
?>
<form action="test.php" method="post">
<div>
    请输入名称：<input type="text" name="name" value="<?php echo $value; ?>" /> &nbsp;
    <input type="submit" value="查询" />
</div>
</form>
<br />
<table width="100%" border="1" cellpadding="0" cellspacing="0">
    <tr>
        <td>代号</td>
        <td>汽车名称</td>
        <td>价格</td>
        <td>油耗</td>
        <td>功率</td>
    </tr>
    
    <?php

        $sql = "select * from Car".$cx;
        $attr = $db->Query($sql);
        
        foreach($attr as $v)
        {
            //处理Name
            $rp = "<span style=‘color:red‘>{$value}</span>";
            $str = str_replace($value,$rp,$v[1]);
            echo "<tr>
                <td>{$v[0]}</td>
                <td>{$str}</td>
                <td>{$v[7]}</td>
                <td>{$v[4]}</td>
                <td>{$v[5]}</td>
            </tr>";
        }
    
    ?>
</table>

多项查询页面

<h1>汽车查询页面</h1>
<br />
<?php
    include("./DBDA.class.php");
    $db = new DBDA();
    
      $cx="";
    $value="";
    
    $tj1 = " 1=1"; //条件1的判断
    $tj2 = " 1=1"; //条件2的判断
    
    if(!empty($_POST["name"]))
    {
        $tj1 = " Name like ‘%{$_POST[‘name‘]}%‘";
    }
    if(!empty($_POST["brand"]))
    {
        $tj2 = " Brand = ‘{$_POST[‘brand‘]}‘";
    }
    
    $cx = " where {$tj1} and {$tj2} ";
?>
<form action="test.php" method="post">
<div>
    请输入名称：<input type="text" name="name" value="<?php echo $value; ?>" /> &nbsp;
    系列：<input type="text" name="brand" />&nbsp;
    <input type="submit" value="查询" />
</div>
</form>
<br />
<table width="100%" border="1" cellpadding="0" cellspacing="0">
    <tr>
        <td>代号</td>
        <td>汽车名称</td>
        <td>系列</td>
        <td>价格</td>
        <td>油耗</td>
        <td>功率</td>
    </tr>
    
    <?php

        $sql = "select * from Car".$cx;
        $attr = $db->Query($sql);
        echo $sql;
        
        foreach($attr as $v)
        {
            //处理Name
            $rp = "<span style=‘color:red‘>{$value}</span>";//让结果重点显示

$str = str_replace($value,$rp,$v[1]);
            echo "<tr>
                <td>{$v[0]}</td>
                <td>{$str}</td>
                <td>{$v[2]}</td>
                <td>{$v[7]}</td>
                <td>{$v[4]}</td>
                <td>{$v[5]}</td>
            </tr>";
        }
    
    ?>
    
</table>