IF和ELSE都不会触发php脚本流！为什么？

分类：编程问答

如何解决IF和ELSE都不会触发php脚本流！为什么？

伙计，

在条件之前，我并没有杀死脚本流

die();

因此，两个触发之一应触发： 如果 否则

但是他们没有。

if(!$result_2)
    {
        echo __LINE__; echo "<br>"; //LINE 92: THIS LINE IN 'IF' DOES NOT TRIGGER. NEITHER THE LINE IN THE 'ELSE'. WHY ?
        
        die("Fetching Error");
    }
    while($row = mysqli_fetch_array($result_2,MYSQLI_ASSOC))
    {
        echo __LINE__; echo "<br>";//LINE 98: THIS LINE IS LIKE AN 'ELSE'. IT  DOES NOT TRIGGER. NEITHER THE LINE IN THE 'IF'. WHY ?

第92行（IF）应该触发，或者第98行（类似于ELSE）触发。

请注意代码中的注释，以了解脚本无故终止流的位置。

<?php

$query_2 = "SELECT id,page_url,link_anchor_text,page_description,keyphrases,keywords FROM links WHERE keywords = ? ORDER by id LIMIT $offset,$limit";
$stmt_2 = mysqli_stmt_init($conn);
if(mysqli_stmt_prepare($stmt_2,$query_2))
{
    echo __LINE__; echo "<br>";//LINE 84: THIS LINE GETS TRIGGERED AND ECHOED IN TEST. LAST LINE THAT GETS ECHOED.
    
    mysqli_stmt_bind_param($stmt_2,'s',$keywords);
    mysqli_stmt_execute($stmt_2);           
    $result_2 = mysqli_stmt_get_result($stmt_2);
    
    if(!$result_2)
    {
        echo __LINE__; echo "<br>"; //LINE 92: THIS LINE IN 'ELSE' DOES NOT TRIGGER. NEITHER THE LINE IN THE 'IF'. WHY ?
        
        die("Fetching Error");
    }

什么是杀死脚本流？

上下文：

<?php

echo __LINE__; echo "<br>"; //LINE 16: THIS LINE GETS TRIGGERED AND ECHOED IN TEST

if(!ISSET($_GET['keywords']))
{
    echo __LINE__; echo "<br>";
    
    die("Type your keywords");
}

$keyword = $_GET['keywords'];

//Check if the PAGE NUMBER is specified or not and if it's a numer or not. If not,return the default: 1.
$page = ISSET($_GET['page']) && is_numeric($_GET['page']) ? $_GET['page'] : 1;

//Check if the PAGE RESULT LIMIT is specified or not and if it's a numer or not. If not,return the default: 1.
$limit = ISSET($_GET['limit']) && is_numeric($_GET['limit']) ? $_GET['limit'] : 1;

$query_1 = "SELECT COUNT(id) FROM links WHERE keywords = ?";
$stmt_1 = mysqli_stmt_init($conn);
if(mysqli_stmt_prepare($stmt_1,$query_1))
{
    echo __LINE__; echo "<br>";//LINE 57: THIS LINE GETS TRIGGERED AND ECHOED IN TEST. BUT WHY SCRIPT FLOW DOES NOT GO BEYOND THIS LINE ?
    
    mysqli_stmt_bind_param($stmt_1,$keywords);
    mysqli_stmt_execute($stmt_1);
    $result_1 = mysqli_stmt_bind_result($stmt_1,$row_count);            
    
    mysqli_stmt_fetch($stmt_1);
}
else
{
    echo __LINE__; echo "<br>"; //LINE 67
    
    printf("Error: %s.\n",mysqli_stmt_error($stmt_1));
    printf("Error: %d.\n",mysqli_stmt_errno($stmt_1));
    die("A. Prepare failed!");
}

mysqli_stmt_close($stmt_1);

//$total_pages = ceil($result_1/$limit); //SHOULD I KEEP THIS LINE OR THE ONE BELOW THIS ONE ?
$total_pages = ceil($row_count/$limit); //SHOULD I KEEP THIS LINE OR THE ONE ABOVE THIS ONE ?
$offset = (($page * $limit) - $limit);

$query_2 = "SELECT id,$keywords);
    mysqli_stmt_execute($stmt_2);           
    $result_2 = mysqli_stmt_get_result($stmt_2);
    
    if(!$result_2)
    {
        echo __LINE__; echo "<br>"; //LINE 92: THIS LINE IN 'IF' DOES NOT TRIGGER. NEITHER THE LINE IN THE 'ELSE'. WHY ?
        
        die("Fetching Error");
    }
    while($row = mysqli_fetch_array($result_2,MYSQLI_ASSOC))
    {
        echo __LINE__; echo "<br>";//LINE 98: THIS LINE IS LIKE AN  'ELSE'. IT DOES NOT TRIGGER. NEITHER THE LINE IN THE 'IF'. WHY ?
        
        echo "LIMIT: $limit<br>";
        echo "ROW COUNT: $row_count<br><br>";
        echo "TOTAL PAGES: $total_pages<br><br>";
        
        //Retrieve Values.
        $id = $row["id"];
        $page_url = $row["page_url"];
        $link_anchor_text = $row["link_anchor_text"];
        $page_description = $row["page_description"];
        $keyphrases= $row["keyphrases"];
        $keywords = $row["keywords"];
        
        echo "Id: $id<br>";
        echo "Page Url: $page_url<br>";
        echo "Link Anchor Text: $link_anchor_text<br>";
        echo "Page Description: $page_description<br>";
        echo "Keyphrases: $keyphrases<br>";
        echo "Keywords: $keywords<br>";
        echo "<br>";
        echo "<br>";
    }
}
else
{
    echo __LINE__; echo "<br>";//Line 124
    
    printf("Error: %s.\n",mysqli_stmt_error($stmt_2));
    printf("Error: %d.\n",mysqli_stmt_errno($stmt_2));
    die("B. Prepare failed!");
}

此外，在这2个中，哪个是正确的？

$total_pages = ceil($result_1/$limit); //SHOULD I KEEP THIS LINE OR THE ONE BELOW THIS ONE ?

$total_pages = ceil($row_count/$limit); //SHOULD I KEEP THIS LINE OR THE ONE ABOVE THIS ONE ?

更新 我的代码现在看起来像这样。 在CAPITALS的代码注释中清楚地提到了我的问题。

当前问题：

问题1： 分页部分仅显示从PAGE 1到PAGE 1的链接。无法显示到PAGE 2的链接。配置为每页显示1行的代码。由于有2个匹配的行，因此自然会有2页显示所有结果。为什么分页部分无法显示从PAGE 1到PAGE 2的链接？

error_reporting.php 

<?php

ini_set('display_errors','1');
ini_set('display_startup_errors','1');
ini_set('error_reporting',E_ALL);
?>

<?php
require 'conn.php';
require 'error_reporting.php';
?>

<!DOCTYPE HTML">
<html>

<head>
<meta name="viewport" content="width-device=width,initial-scale=1">
</head>
<body>

<form method='GET' action="<?php echo $_SERVER['PHP_SELF'];?>?keywords=$keywords&limit=$limit&page=1">
<label for="keywords">Keywords:*</label>
<input type="text" name="keywords" id="keywords" placeholder="Input Keywords" required>
<br>
<label for="limit">Results per Page</label>
<select name="limit" id="limit">
<option value="1">1</option>
<option value="10">10</option>
<option value="25">25</option>
<option value="50">50</option>
<option value="100">100</option>
</select>
<br>
<button name="search" id="search" value=" ">Search</button><br>
<button type="submit" name="search" id="search" value="search">Search</button>
<br>
<input type="reset">
<br>
</form>

<?php

echo __LINE__; echo "<br>"; //LINE 16: THIS LINE GETS TRIGGERED AND ECHOED IN TEST

if(!ISSET($_GET['keywords']))
{
    echo __LINE__; echo "<br>";
    
    die("Type your keywords");
}

$keywords = $_GET['keywords'];

//Check if the PAGE NUMBER is specified or not and if it's a numer or not. If not,$query_1))
{
    echo __LINE__; echo "<br>";//LINE 57: THIS LINE GETS TRIGGERED AND ECHOED IN TEST. 
    
    mysqli_stmt_bind_param($stmt_1,$row_count);
    mysqli_stmt_fetch($stmt_1);
    echo "ROW COUNT: $row_count<br><br>";
}
else
{
    echo __LINE__; echo "<br>"; //LINE 67
    
    printf("Error: %s.\n",mysqli_stmt_errno($stmt_1));
    die("A. Prepare failed!");
}

mysqli_stmt_close($stmt_1);

$total_pages = ceil($row_count/$limit);
$offset = (($page * $limit) - $limit);

$query_2 = "SELECT id,$query_2)) //LINE 82: 
{
    echo __LINE__; echo "<br>";//LINE 84: THIS LINE GETS TRIGGERED AND SO PREPARED STATEMENT DID NOT FAIL AT LINE 82!
    
    mysqli_stmt_bind_param($stmt_2,MYSQLI_ASSOC))//LINE 96: THIS LINE IS LIKE AN 'ELSE'. IT DOES NOT TRIGGER. NEITHER THE LINE IN THE 'IF'. WHY ?
    {
        echo __LINE__; echo "<br>";
        
        echo "LIMIT: $limit<br>";
        echo "ROW COUNT: $row_count<br><br>";
        echo "TOTAL PAGES: $total_pages<br><br>";
        
        //Retrieve Values.
        $id = $row["id"];
        $page_url = $row["page_url"];
        $link_anchor_text = $row["link_anchor_text"];
        $page_description = $row["page_description"];
        $keyphrases = $row["keyphrases"];
        $keywords = $row["keywords"];
        
        echo "Id: $id<br>";
        echo "Page Url: $page_url<br>";
        echo "Link Anchor Text: $link_anchor_text<br>";
        echo "Page Description: $page_description<br>";
        echo "Keyphrases: $keyphrases<br>";
        echo "Keywords: $keywords<br>";
        echo "<br>";
        echo "<br>";
    }
}
else
{
    echo __LINE__; echo "<br>";//LINE 124
    
    printf("Error: %s.\n",mysqli_stmt_errno($stmt_2));
    die("B. Prepare failed!");
}

mysqli_stmt_close($stmt_2);

//PAGINATION SECTION STARTS FROM HERE:
//WHY PAGINATION SECTION FAILS TO DISPLAY ? ONLY A LINK TO PAGE 1 IS SHOWN WHEN YOU LOAD PAGE 1. NO LINK TO PAGE 2. THERE ARE 2 MATCHING ROWS. SCRIPT FIXED TO SHOW 1 ROW PER PAGE. AND SO,2 PAGES SHOULD DISPLAY ALL RESULTS. HENCE,PAGINATION SECTION SHOULD SHOW A LINK TO PAGE 2 FROM PAGE 1. BUT PAGE 1 ONLY LINKS TO ITSELF IN THE PAGINATION SECTION.
if($page>$total_pages) //If Page Number is greater than Total Pages,show only a link to FINAL PAGE.
{
    echo "?><a href=\"pagination_test.php?limit=$limit&page=$total_pages\">";?><?php echo "<b> Final Page </b>";?></a><?php 
}
else
{
    $i = 1;
    while($i<=$total_pages)
    {
        if($i<$total_pages)
        {
            echo "<a href=\"pagination_test.php?keywords=$keywords&limit=$limit&page=$i\">";?><?php echo " $i ";?></a><?php 
        }
        elseif($i==$page) //Bold the Current Page Number.
        {
            echo "<a href=\"pagination_test.php?keywords=$keywords&limit=$limit&page=$i\">";?><?php echo "<b> $i </b>";?></a><?php 
        }               
        $i++;
    }
}
?>

再次更新： 问题：Url“＆page =”中缺少。

看这个html：

<form method='GET' action="<?php echo $_SERVER['PHP_SELF'];?>?keywords=$keywords&limit=$limit&page=1">

如您所见，单击表单按钮后，您应该被发送到： pagination_test_2.php？keywords = $ keywords＆limit = $ limit＆page = 1“

但是你猜怎么着？您被发送到： ？keywords = $ keywords＆limit = $ limit＆search = search“

URL中“＆page = 1”部分在哪里？ 另外，如何不将“ search = search”添加到网址中？

<?php
require 'conn.php';
require 'error_reporting.php';
?>

<!DOCTYPE HTML">
<html>

<head>
<meta name="viewport" content="width-device=width,initial-scale=1">
</head>
<body>

<form method='GET' action="<?php echo $_SERVER['PHP_SELF'];?>?keywords=$keywords&limit=$limit&page=1">
<label for="keywords">Keywords:*</label>
<input type="text" name="keywords" id="keywords" placeholder="Input Keywords" required>
<br>
<label for="limit">Results per Page</label>
<select name="limit" id="limit">
<option value="1">1</option>
<option value="10">10</option>
<option value="25">25</option>
<option value="50">50</option>
<option value="100">100</option>
</select>
<br>
<button name="search" id="search" value=" ">Search</button><br>
<button type="submit" name="search" id="search" value="search">Search</button>
<br>
<input type="reset">
<br>
</form>

<?php

echo __LINE__; echo "<br>";

if(!ISSET($_GET['keywords']))
{
    echo __LINE__; echo "<br>";
    
    die("Type your keywords");
}

$keywords = $_GET['keywords'];

//Check if the PAGE NUMBER is specified or not and if it's a numer or not. If not,$query_1))
{
    echo __LINE__; echo "<br>";
    
    mysqli_stmt_bind_param($stmt_1,$row_count);
    mysqli_stmt_fetch($stmt_1);
    echo "ROW COUNT: $row_count<br><br>";
}
else
{
    echo __LINE__; echo "<br>";
    
    printf("Error: %s.\n",$limit";
$stmt_2 = mysqli_stmt_init($conn);

if(mysqli_stmt_prepare($stmt_2,$query_2))
{
    echo __LINE__; echo "<br>";
    
    mysqli_stmt_bind_param($stmt_2,$keywords);
    mysqli_stmt_execute($stmt_2);           
    $result_2 = mysqli_stmt_get_result($stmt_2);
        
    if(!$result_2)
    {
        echo __LINE__; echo "<br>";
        
        die("Fetching Error");
    }
    
    while($row = mysqli_fetch_array($result_2,MYSQLI_ASSOC))
    {
        echo __LINE__; echo "<br>";
        
        echo "LIMIT: $limit<br>";
        echo "ROW COUNT: $row_count<br><br>";
        echo "TOTAL PAGES: $total_pages<br><br>";
        
        //Retrieve Values.
        $id = $row["id"];
        $page_url = $row["page_url"];
        $link_anchor_text = $row["link_anchor_text"];
        $page_description = $row["page_description"];
        $keyphrases = $row["keyphrases"];
        $keywords = $row["keywords"];
        
        echo "Id: $id<br>";
        echo "Page Url: $page_url<br>";
        echo "Link Anchor Text: $link_anchor_text<br>";
        echo "Page Description: $page_description<br>";
        echo "Keyphrases: $keyphrases<br>";
        echo "Keywords: $keywords<br>";
        echo "<br>";
        echo "<br>";
    }
}
else
{
    echo __LINE__; echo "<br>";
    
    printf("Error: %s.\n",mysqli_stmt_errno($stmt_2));
    die("B. Prepare failed!");
}

mysqli_stmt_close($stmt_2);

if($page>$total_pages) //If Page Number is greater than Total Pages,show only a link to FINAL PAGE.
{
    echo "<a href=\"pagination_test.php?keywords=$keywords&limit=$limit&page=$total_pages\">"; echo "<b> Final Page </b>";?></a><?php
}
else
{
    $i = 1;
    while($i<=$total_pages)
    {
        if($i<$total_pages && $i!=$page)
        {
            echo "<a href=\"pagination_test_2.php?keywords=$keywords&limit=$limit&page=$i\">"; echo " $i ";?></a><?php
        }
        elseif($i==$page) //Bold the Current Page Number.
        {
            echo "<a href=\"pagination_test_2.php?keywords=$keywords&limit=$limit&page=$i\">"; echo "<b> $i </b>";?></a><?php
        }
        else
        {
            echo "<a href=\"pagination_test_2.php?keywords=$keywords&limit=$limit&page=$i\">"; echo " $i ";?></a><?php
        }
        $i++;
    }
}
?>

错别字位于分页部分的网址上。现在，我修复了它们，因此分页部分工作正常。 有人可以友好地签出我的代码，并让我知道如果不是真的需要淘汰哪些行。

解决方法

我认为这两行都没有达到，因为该语句有效，但返回零行。在$query_2 = ...之前，您可以在$row_count上添加检查以查看是否有任何行吗？

要回答第二个问题，$total_pages = ceil($row_count/$limit);是正确的答案，因为mysqli_stmt_bind_result返回一个布尔值，因此$result_1是对还是错。

我个人喜欢使用面向对象的样式，而不喜欢您使用的过程样式，因为我发现它更易于阅读，但选择是您自己的。

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