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PHP PDO，排除具有空字段值的行

phpmysql
4

我正在使用这个示例代码 output6.php

如果empire_name返回null，我想跳过相关的行。有什么想法或建议将不胜感激。 谢谢！

<!DOCTYPE html>
<html>
<body>

<?php
echo "<table style='border: solid 1px black;'>";
  echo "<tr>
    <th>Empire Name</th>
    <th>Win?</th>
    <th>Building 1</th>
    <th>Building 2</th>
    <th>Building 3</th>
    <th>Building 4</th>
    <th>Building 5</th>
    <th>Building 6</th>
    <th>Building 7</th>
    <th>Building 8</th>
    <th>Building 9</th>
    </tr>";

class TableRows extends RecursiveIteratorIterator { 
     function __construct($it) { 
         parent::__construct($it, self::LEAVES_ONLY); 
     }

     function current() {
         return "<td style='width: 150px; border: 1px solid black;'>" . parent::current(). "</td>";
     }

     function beginChildren() { 
         echo "<tr>"; 
     } 

     function endChildren() { 
         echo "</tr>" . "\n";
     } 
} 

$servername = "xxx";
$username = "xxx";
$password = "xxx";
$dbname = "xxx";

try {
     $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
     $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
     $stmt = $conn->prepare("SELECT empire_name, win, building_1, building_2, building_3, building_4, building_5, building_6, building_7, building_8, building_9 FROM ft_form_2 "); 
     $stmt->execute();

     // set the resulting array to associative
     $result = $stmt->setFetchMode(PDO::FETCH_ASSOC); 

     foreach(new TableRows(new RecursiveArrayIterator($stmt->fetchAll())) as $k=>$v) { 
         echo $v;
     }
}
catch(PDOException $e) {
     echo "Error: " . $e->getMessage();
}
$conn = null;
echo "</table>";
?>  

</body>
</html>

我尝试搜索了一下，但是我不知道该搜什么

谢谢！

我的当前结果null = 空行，图片链接

我认为这很接近... PDO和IS NOT NULL函数 但我不确定如何在当前代码中实现（我尝试了几个变化）

另一种变化-相同的结果（output3.php），更接近所需的最终结果

<?php
define("DB_HOST", "xxx");    // Using Constants
define("DB_USER", "xxx");
define("DB_PASS", "xxx");
define("DB_NAME", "xxx");

try {       // << using Try/Catch() to catch errors!

$dbc = new PDO("mysql:host=".DB_HOST.";dbname=".DB_NAME.";charset-utf8",DB_USER,DB_PASS);
}catch(PDOException $e){ echo $e->getMessage();}

if($dbc <> true){
    die("<p>There was an error</p>");
}

$print = ""; // assign an empty string 

$stmt = $dbc->query("SELECT * FROM ft_form_2"); // fetch data
$stmt->setFetchMode(PDO::FETCH_OBJ);

if($stmt->execute() <> 0)
{

    $print .= '<table border="1px">';
    $print .= '<tr><th>Empire_Name</th>';
    $print .= '<th>Win</th>';
    $print .= '<th>Building_1</th>';
    $print .= '<th>Building_2</th>';
    $print .= '<th>Building_3</th>';
    $print .= '<th>Building_4</th>';
    $print .= '<th>Building_5</th>';
    $print .= '<th>Building_6</th>';
    $print .= '<th>Building_7</th>';
    $print .= '<th>Building_8</th>';
    $print .= '<th>Building_9</th> </tr>';

    while($ft_form_2 = $stmt->fetch()) // loop and display data
    {

        $print .= '<tr>';
        $print .= "<td>{$ft_form_2->empire_name}</td>";
        $print .= "<td>{$ft_form_2->win}</td>";
        $print .= "<td>{$ft_form_2->building_1} <br> {$ft_form_2->building_1_notes} </td>";
        $print .= "<td>{$ft_form_2->building_2} <br> {$ft_form_2->building_2_notes} </td>";
        $print .= "<td>{$ft_form_2->building_3} <br> {$ft_form_2->building_3_notes} </td>";
        $print .= "<td>{$ft_form_2->building_4} <br> {$ft_form_2->building_4_notes} </td>";
        $print .= "<td>{$ft_form_2->building_5} <br> {$ft_form_2->building_5_notes} </td>";
        $print .= "<td>{$ft_form_2->building_6} <br> {$ft_form_2->building_6_notes} </td>";
        $print .= "<td>{$ft_form_2->building_7} <br> {$ft_form_2->building_7_notes} </td>";
        $print .= "<td>{$ft_form_2->building_8} <br> {$ft_form_2->building_8_notes} </td>";
        $print .= "<td>{$ft_form_2->building_9} <br> {$ft_form_2->building_9_notes} </td>";
        $print .= '</tr>';
    }

    $print .= "</table>";
    echo $print;
}
?>
2个回答
1

根据你在问题中提到的使用 IS NOT NULL 的逻辑，你走在了正确的道路上。仅从数据库返回你需要的内容比在 PHP 中获取所有内容然后进行过滤要更加高效。

你在这里的陈述

$stmt = $conn->prepare("SELECT empire_name, win, building_1, building_2, building_3, building_4, building_5, building_6, building_7, building_8, building_9 FROM ft_form_2 ");

你可以在结尾处添加一个 where 条件

$stmt = $conn->prepare("SELECT empire_name, win, building_1, building_2, building_3, building_4, building_5, building_6, building_7, building_8, building_9 FROM ft_form_2 WHERE empire_name IS NOT NULL ");

然后您的数据库将进行过滤。第二个示例也可以应用相同的方法。
$stmt = $dbc->query("SELECT * FROM ft_form_2 WHERE empire_name IS NOT NULL");
-1

在打印行之前添加简单的检查。类似以下内容。

while($ft_form_2 = $stmt->fetch()) // loop and display data
{
    if( !empty($ft_form_2->empire_name) && !is_null($ft_form_2->empire_name) )
    {
        $print .= '<tr>';
        $print .= "<td>{$ft_form_2->empire_name}</td>";
        $print .= "<td>{$ft_form_2->win}</td>";
        $print .= "<td>{$ft_form_2->building_1} <br> {$ft_form_2->building_1_notes} </td>";
        $print .= "<td>{$ft_form_2->building_2} <br> {$ft_form_2->building_2_notes} </td>";
        $print .= "<td>{$ft_form_2->building_3} <br> {$ft_form_2->building_3_notes} </td>";
        $print .= "<td>{$ft_form_2->building_4} <br> {$ft_form_2->building_4_notes} </td>";
        $print .= "<td>{$ft_form_2->building_5} <br> {$ft_form_2->building_5_notes} </td>";
        $print .= "<td>{$ft_form_2->building_6} <br> {$ft_form_2->building_6_notes} </td>";
        $print .= "<td>{$ft_form_2->building_7} <br> {$ft_form_2->building_7_notes} </td>";
        $print .= "<td>{$ft_form_2->building_8} <br> {$ft_form_2->building_8_notes} </td>";
        $print .= "<td>{$ft_form_2->building_9} <br> {$ft_form_2->building_9_notes} </td>";
        $print .= '</tr>';
    }
}

或者

您可以在查询中添加WHERE条件。例如：

 WHERE empire_name IS NOT NULL AND empire != ''
@MikeP，请在您发现此回答有帮助时标记我的答案。 - Muhammad Hassaan
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