条件查询php

页面1.php

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
</head>

<body>

<h1>信息</h1>
<form action="1.php" method="post">
<div>
    请输入姓名：<input type="text" name="name" />
　　电话：<input type="text" name="tel" />
    <input type="submit" value="查询" />
</div>
</form>
<br />
<table width="100%" border="1" cellpadding="0" cellspacing="0">

<tr>
    <td>代号</td>
    <td>姓名</td>
    <td>电话</td>
    <td>分组</td>
</tr>

<?php

//实现两个逻辑
//1.如果没有POST数据，查所有
//2.如果有POST数据，根据条件查

$db = new MySQLi("localhost","root","root","dbname");

/*if(POST传值)
{
    SQL语句1
}
else
{
    SQL语句2
}
*/

$tj = " 1=1 "; //默认条件,前后最好带有空格
$tj2 =" 1=1 ";
$name = "";//外面要写一个默认值，若不写，当不走if时会没有值
$tel = "";
if(!empty($_POST["name"]))
{
    $name = $_POST["name"];
    $tj = " Name like '%{$name}%' ";
}

if(!empty($_POST["tel"]))
{
    $tel = $_POST["tel"];
    $tj = " Tel = '{$tel}' ";
}
//将条件拼接到SQL语句
 $sql = "select * from contacts where {$tj} and {$tj2}";

//echo $sql; 
$result = $db->query($sql); 
while($arr = $result->fetch_row()) { 
//关键字的特殊显示  
$str = str_replace($name,"<mark>{$name}</mark>",$arr[1]); 
//查找替换 
//substr_replace(); //指定位置替换 
echo "<tr> <td>{$arr[0]}</td> 
<td>{$str}</td> 
<td>{$arr[2]}</td> 
<td>{$arr[3]}</td> 
</tr>"; } 
?> 
</table> 
</body> 
</html>