php 中的未定义索引错误（下拉过滤器不起作用）

Question

嘿，我对这个问题进行了很多搜索，但我尝试的所有方法都没有用。 :(

我的代码有 3 个下拉菜单，它们应该像搜索过滤器一样工作，但每次我 select 从下拉菜单中选择一个选项时，我都会收到 3 行的未统一索引错误，如果我更改另一个下拉菜单，则另外两个过滤器被忽略... :(

这只是第一个下拉菜单的代码：

<?php  
  //when the filter changes, this php is called

 $output = '';


if(isset($_POST["businessUnit"]))  
{  
    if($_POST["businessUnit"] != '')  
    {
        if($_POST["productGroup"] != '') //first undefined index
        {
            $sql = "SELECT * FROM item WHERE businessUnit =         '".$_POST["businessUnit"]."' and productGroup = '".$_POST["productGroup"]."'";
        }
        else if($_POST["deviceType"] != '') //second undefined index
        {
            $sql = "SELECT * FROM item WHERE businessUnit = 
'".$_POST["businessUnit"]."' and productGroup = '".$_POST["deviceType"]."'";
        }
        else if($_POST["productGroup"] != '' && $_POST["deviceType"] != '') //third undefined index error
        {
            $sql = "SELECT * FROM item WHERE businessUnit = '".$_POST["businessUnit"]."' and productGroup = '".$_POST["productGroup"]."' and deviceType = '".$_POST["deviceType"]."'";
        }
        else
        {
            $sql = "SELECT * FROM item WHERE businessUnit = '".$_POST["businessUnit"]."'";
        }  
    }
    else  
    {  
        $sql = "SELECT * FROM item";  
    }  
    $result = sqlsrv_query($connect, $sql);  
    while($row = sqlsrv_fetch_array($result))  
    {  
        $output .= "<tr><td>".
                $row['businessUnit']."</td><td>".
                $row['productGroup']."</td><td>".
                $row['deviceType']."</td><td>".
                $row['serialNumber']."</td><td>".    
                $row['location']."</td><td>".
                $row['condition']."</td><td>".
                $row['itemDescription']."</td><td>
                <input type='checkbox'></input></td></tr>";  
    }  
    echo $output;  
}
else{
    $_POST["businessUnit"] = "";
}
?>

Answer 1

来处理undefined index的错误，$array[$key] != ""是不行的，必须先用isset()才行不等于空白检查。请参阅下面的解决方案，它可能有效。

if (isset($_POST["businessUnit"]))
        {
            if ($_POST["businessUnit"] != '')
            {
                if (isset($_POST["productGroup"]) && $_POST["productGroup"] != '') //first undefined index
                {
                    $sql = "SELECT * FROM item WHERE businessUnit =         '" . $_POST["businessUnit"] . "' and productGroup = '" . $_POST["productGroup"] . "'";
                } else if (isset($_POST["deviceType"]) && $_POST["deviceType"] != '') //second undefined index
                {
                    $sql = "SELECT * FROM item WHERE businessUnit = 
'" . $_POST["businessUnit"] . "' and productGroup = '" . $_POST["deviceType"] . "'";
                } else if (isset($_POST["productGroup"]) && $_POST["productGroup"] != '' && isset($_POST["deviceType"]) && $_POST["deviceType"] != '') //third undefined index error
                {
                    $sql = "SELECT * FROM item WHERE businessUnit = '" . $_POST["businessUnit"] . "' and productGroup = '" . $_POST["productGroup"] . "' and deviceType = '" . $_POST["deviceType"] . "'";
                } else
                {
                    $sql = "SELECT * FROM item WHERE businessUnit = '" . $_POST["businessUnit"] . "'";
                }
            } else
            {
                $sql = "SELECT * FROM item";
            }
            $result = sqlsrv_query($connect, $sql);
            while ($row = sqlsrv_fetch_array($result))
            {
                $output .= "<tr><td>" .
                        $row['businessUnit'] . "</td><td>" .
                        $row['productGroup'] . "</td><td>" .
                        $row['deviceType'] . "</td><td>" .
                        $row['serialNumber'] . "</td><td>" .
                        $row['location'] . "</td><td>" .
                        $row['condition'] . "</td><td>" .
                        $row['itemDescription'] . "</td><td>
                <input type='checkbox'></input></td></tr>";
            }
            echo $output;
        } else
        {
            $_POST["businessUnit"] = "";
        }
    }

Answer 2

我不明白你想做什么。请 post 显示快照并明确说明您要做什么。你可以这样写：

echo "<pre>";print_r($_POST);
                 after $output = '';

看看 $_POST 变量中有什么，如果没有找到：

$_POST["productGroup"]

在 $_POST 中你会得到未定义的索引。因此，请确保您在 $_POST 请求中传递它。

php 中的未定义索引错误（下拉过滤器不起作用）

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