Question

我需要为这3个信息创建过滤功能：用户的类别，价格和折扣，以便将1个信息或任何2个信息一起过滤，或者将所有3个信息一起过滤。

我使用此方法过滤单个信息并成功显示结果，但当我尝试使用此方法过滤任何2或3个信息时，它无法过滤所有内容。

<?php
//filter category only
if (isset($_GET['f_category']) && $_GET['f_category'] != ""){

    $f_category = $_GET['f_category'];
    $sql = "SELECT * FROM post_ads WHERE sup_category='$f_category'";    
}

//filter price only
if (isset($_GET['min_price']) && $_GET['min_price'] != "" && $_GET['max_price'] && $_GET['max_price'] != "") {

    $min_price = $_GET['min_price'];
    $max_price = $_GET['max_price'];
    $sql = "SELECT * FROM post_ads WHERE sup_price>='$min_price' AND sup_price<='$max_price'"; 
}

// filter discount only
if (isset($_GET['f_discount']) && $_GET['f_discount'] != ""){

    $f_discount = $_GET['f_discount'];
    $sql = "SELECT * FROM post_ads WHERE sup_discount='$f_discount'";    
}

//filter category and price
if (isset($_GET['f_category']) && $_GET['f_category'] != "" || $_GET['min_price'] && $_GET['min_price'] != "" && $_GET['max_price'] && $_GET['max_price'] != ""){

    $f_category = $_GET['f_category'];
    $min_price = $_GET['min_price'];
    $max_price = $_GET['max_price'];
    $sql = "SELECT * FROM post_ads WHERE sup_category='$f_category'
    AND sup_price>='$min_price' AND sup_price<='$max_price'";        
}

//filter category and discount
if (isset($_GET['f_category']) && $_GET['f_category'] != "" || $_GET['f_discount']
&& $_GET['f_discount'] != ""){

    $f_category = $_GET['f_category'];
    $f_discount = $_GET['f_discount'];
    $sql = "SELECT * FROM post_ads WHERE sup_category='$f_category'
    AND sup_discount='$f_discount'";   
}

if(isset($sql)){

$result = mysql_query($sql, $con1);
while($rows=mysql_fetch_array($result))
 {
   //display results
 }
}?>

我可以知道问题是什么，我该如何解决？

Answer 1

您可以根据原始条件将每个子句添加到数组中，并在最后将它们组合在一起。

<?php
    $clauses=array();

    if( isset( $_GET['f_category'] ) && !empty( $_GET['f_category'] ) ){
        $clauses[] = "`sup_category` = '{$_GET['f_category']}'";   
    }
    if ( isset( $_GET['min_price'], $_GET['max_price'] ) && !empty( $_GET['min_price'] )  && !empty( $_GET['max_price'] ) ) {
        $clauses[]="`sup_price` >= '{$_GET['min_price']}'";
        $clauses[]="`sup_price` <= '{$_GET['max_price']}'";
    }
    if ( isset( $_GET['f_discount'] ) && !empty( $_GET['f_discount'] ) ){
        $clauses[]="`sup_discount` = '{$_GET['f_discount']}'";   
    }

    $where = !empty( $clauses ) ? ' where '.implode(' and ',$clauses ) : '';
    $sql = "SELECT * FROM `post_ads` " . $where; 

    echo $sql;

    if(isset($sql)){

         $result = mysql_query($sql, $con1);
         while($rows=mysql_fetch_array($result)){
           /*display results*/
         }
    }
?>

使用此网址运行上述（已编辑的版本）

https://locahost/stack/sql?f_category=bananas&min_price=200&max_price=500&f_discount=32

会产生如下查询：

SELECT * FROM `post_ads` where `sup_category` = 'bananas' 
   and `sup_price` >= '200' and `sup_price` <= '500' and `sup_discount` = '32'

这一切都说 - 没有关心你的代码非常容易受到sql注入 - 不推荐使用mysql_*函数套件，强烈建议不要使用它们。在进入太深之前，请使用mysqli切换到prepared statements - 避免心痛' - ）

Answer 2

我认为您的网址格式如下：

1＆GT; example.com?f_category=test //仅选择f_category过滤器时

2 - ; example.com?f_category=test&min_price=50 //选择f_category和min_price为过滤器时。等等......

因此，您只需将其编码为：

<?php


$querySubString = "1 = 1";

if (isset($_GET['f_category']) && $_GET['f_category'] != ""){

$f_category = $_GET['f_category'];
$querySubString .= " AND sup_category = '$f_category' ";
}

if (isset($_GET['min_price']) && $_GET['min_price'] != ""){

$min_price = $_GET['min_price'];
$querySubString .= "AND sup_price >= '$min_price' ";
}

if (isset($_GET['max_price']) && $_GET['max_price'] != ""){

$max_price = $_GET['max_price'];
$querySubString .= "AND sup_price <= '$max_price' ";
}

if (isset($_GET['f_discount']) && $_GET['f_discount'] != ""){

$f_discount = $_GET['f_discount'];
$querySubString .= " AND sup_discount= '$f_discount' ";
}
 $sql = "SELECT * FROM post_ads WHERE $querySubString ";

if(isset($sql)){

$result = mysql_query($sql, $con1);
while($rows=mysql_fetch_array($result))
 {
   //display results
 }


?>

Answer 3

为简单起见，请重写代码，使其首先处理输入，然后构建查询。这使得我们双方都更具可读性，您很可能会在此过程中解决您的问题。

此外，请不要使用mysql_，它不安全，已被mysqli_方法取代。

php中的单个和多个数据过滤器

3 个答案: