Question

请有人可以向我解释如何调整我的代码以使其如果mysql表中不存在记录/值它会回显一段文本？谢谢。

<?php

$reviews_set = get_reviews();

 ?>
<h3>Latest Reviews</h3>
<?php
while ($reviews = mysql_fetch_array($reviews_set)) {
 ?>
 <div class="prof-content-box" id="reviews">
 <div class="message_pic">
 <?php echo "<a href=\"profile.php?id={$reviews['from_user_id']}\"><img width=\"50px\" height=\"50px\"  src=\"{$prof_photo}\"></a>";?>
 <?php echo "<strong>Review from  {$reviews['display_name']}:</strong><br /><br/> {$reviews['content']}     <br />";


  ?>

Answer 1

使用三元运算符'？：'

样品：

$you_var ?: 'you_text_if_not_exists'

Answer 2

检查你的变量：

<?php (isset($reviews['display_name']) ? $reviews['display_name'] : "entry doesn't exists"; ?>

Answer 3

    <?php

     $reviews_set = get_reviews();

   ?>
   <h3>Latest Reviews</h3>
   <?php
    if(mysql_num_rows($reviews =  mysql_fetch_array($reviews_set))>=1)
    {
    while ($reviews = mysql_fetch_array($reviews_set)) {
    ?>
    <div class="prof-content-box" id="reviews">
    <div class="message_pic">
    <?php echo "<a href=\"profile.php?id={$reviews['from_user_id']}\"><img width=\"50px\" height=\"50px\"  src=\"{$prof_photo}\"></a>";?>
    <?php echo "<strong>Review from  {$reviews['display_name']}:</strong><br /><br/>    {$reviews['content']}     <br />";
    }
    } else {
    echo 'No reviews available';
    }


    ?>

Answer 4

如果要检查表是否有行，请使用以下命令：

$num_rows = mysql_num_rows($reviews_set);

$num_rows将包含行数。

Answer 5

<?php
    $reviews_set = get_reviews();
    ?>
    <h3>Latest Reviews</h3>
    <?php
    if(mysql_num_rows($reviews_set) > 0) {
        while ($reviews = mysql_fetch_array($reviews_set)) {
            ?>
            <div class="prof-content-box" id="reviews">
             <div class="message_pic">
             <?php echo "<a href=\"profile.php?id={$reviews['from_user_id']}\"><img width=\"50px\" height=\"50px\"  src=\"{$prof_photo}\"></a>";?>
             <?php echo "<strong>Review from  {$reviews['display_name']}:</strong><br /><br/> {$reviews['content']}     <br />";
        <? 
        }
    }else{
      echo "No Data";
    }

    ?>

我希望这会有所帮助

如果表值不存在echo文本？

5 个答案: