如果雄蕊对数据库查询不起作用

我正在运行下面的代码，但无法让if语句正常工作。我希望能够删除div如果没有内容，如果有，然后显示它，但目前它要么全部删除它，如果一个数据库条目是空的，而不是只删除1空行。如果雄蕊对数据库查询不起作用

   <?php 
    $con = new mysqli($DBServer, $DBUser, $DBPass, $DBName); 
    if (mysqli_connect_errno()) { 
    echo "Failed to connect to MySQL: " . mysqli_connect_error(); 
    } 
    extract($_GET); 
    { $result = mysqli_query($con,"SELECT * FROM links ORDER by id "); 
    while($row = mysqli_fetch_array($result)) { 

    if ($section=""){ 
    echo""; 
    } 
    elseif ($section="a"){ 
    echo"<div class=\"page-header\">" . $row['section'] . "\</div>"; 
    } 


     echo "<div class=\"links-wrap\"> 
     <div class=\"links-box\"> 
     <div class=\"links-image\"><img src=\"images/links/" . $row['img1'] . "\"></div> 
     <div class=\"links-site-txt\">" . $row['link1'] . "</div> 
     <div class=\"links-desc\">" . $row['desc1'] . "</div> 
     </div> 
     <div class=\"spacer-left\"></div> 
     <div class=\"links-box\"></div> 
     <div class=\"spacer-left\"></div> 
     <div class=\"links-box\"></div> 
      </div>";}} 
     mysqli_close($con); 
     ?>

来源

2014-09-27 tom harrison

你在哪里设置'$ section'？ – Aquillo 2014-09-27 14:29:10

为了通过if或elseif==需要不=比较值。 =通常用于为变量赋值。改变你的代码，如下所示。

$con = new mysqli($DBServer, $DBUser, $DBPass, $DBName); 
if (mysqli_connect_errno()) { 
    echo "Failed to connect to MySQL: " . mysqli_connect_error(); 
} 
extract($_GET); 

$result = mysqli_query($con,"SELECT * FROM links ORDER by id "); 

while($row = mysqli_fetch_array($result)) { 
    $section = $row['section']; 
    if ($section == ""){ 
     echo ""; 
    } 
    elseif ($section == "a"){ 
     echo"<div class=\"page-header\">" . $row['section'] . "\</div>"; 
    } 

    echo "<div class=\"links-wrap\"> 
    <div class=\"links-box\"> 
    <div class=\"links-image\"><img src=\"images/links/" . $row['img1'] . "\"></div> 
    <div class=\"links-site-txt\">" . $row['link1'] . "</div> 
    <div class=\"links-desc\">" . $row['desc1'] . "</div> 
    </div> 
    <div class=\"spacer-left\"></div> 
    <div class=\"links-box\"></div> 
    <div class=\"spacer-left\"></div> 
    <div class=\"links-box\"></div> 
     </div>"; 
} 

mysqli_close($con);

来源

2014-09-27 14:29:34 MH2K9

谢谢你，但我现在得到通知：未定义的变量：第20行的部分？ – 2014-09-27 15:03:33

因为你没有定义'$ section'。将其定义在代码的第一个顶部。 – MH2K9 2014-09-27 15:05:07

对不起，我是新来的PHP，并不确定需要做什么来定义它。它应该从数据库拉值？ – 2014-09-27 15:07:34

<?php 
$con = new mysqli($DBServer, $DBUser, $DBPass, $DBName); 
if (mysqli_connect_errno()) { 
echo "Failed to connect to MySQL: " . mysqli_connect_error(); 
} 
extract($_GET); 
{ $result = mysqli_query($con,"SELECT * FROM links ORDER by id "); 
while($row = mysqli_fetch_array($result)) { 

if ($section == ""){ //double equality for condition check 
echo ""; 
} 
else if ($section == "a"){ 
echo"<div class=\"page-header\">" . $row['section'] . "\</div>"; 
} 


    echo "<div class=\"links-wrap\"> 
    <div class=\"links-box\"> 
    <div class=\"links-image\"><img src=\"images/links/" . $row['img1'] . "\"></div> 
    <div class=\"links-site-txt\">" . $row['link1'] . "</div> 
    <div class=\"links-desc\">" . $row['desc1'] . "</div> 
    </div> 
    <div class=\"spacer-left\"></div> 
    <div class=\"links-box\"></div> 
    <div class=\"spacer-left\"></div> 
    <div class=\"links-box\"></div> 
     </div>";}} 
    mysqli_close($con); 
    ?>

来源

2014-09-27 14:30:36

如果雄蕊对数据库查询不起作用

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