使用PDO匹配数据库中的行时遇到问题 [英] Having issue with matching rows in the database using PDO

问题描述

我正在寻找行数，以检查数据库中是否已存在同一封电子邮件.我尝试了几种机制，但没有成功.当我直接在数据库中运行查询时，它为我提供了行数，但是通过PDO执行时，它为我提供了0.

I am looking to get row count to check if same email is already in database or not. i have tried couple of mechanism but no success. when i run my query directly in the database it gives me the row count but via PDO execute it gives me 0.

我使用了fetchAll方法进行手动计数，甚至使用了行计数方法也不起作用

i have used fetchAll method to manually count, even used rowCount method that also not working

  $sql = 'SELECT count(*) FROM inbox WHERE uid = "'.$email_number.'" AND from_email = "'.$email_f.'"'; 
  $result = $link->prepare($sql); 
  $result->execute(); 
  $number_of_rows = $result->fetchColumn(); 

问题与此$ email_f一起使用，它包含html

issue is with this $email_f, it contains html

SELECT count(*) FROM inbox WHERE uid = "6961" 
AND from_email = "abc Offers <[e-mail]>"

这是我从$ sql打印的查询，当我在phpmyadmin中直接在数据库中执行该查询时，它工作正常.给我3的数量，但是通过执行我得到0.

this is the query which i have printed from $sql and when i execute it in database directly in phpmyadmin, it works fine. give me count of 3 but via execute i get 0.

推荐答案

最有可能在输入数据(或数据库)中存在一些已转换或不可打印的字符.例如，可能存在换行符或特殊编码的符号，或者某些字符(例如<和>)转换为HTML实体.结果，查询中包含<[e-mail]>的文本将永远不会与文本<[e-mail]>匹配.

Most likely there are some converted or non-printable characters in the input data (or database). For example, there could be a linefeed character or a peculiarly encoded symbol, or some characters such as < and > converted into HTML entities. As a result, the query contains <[e-mail]> will never match a text <[e-mail]>.

问题是，这只是一个猜测，没有人能告诉您实际的问题是什么，因为它是您的数据库，您的输入数据并且只有您可以找到问题.

The problem is, this is only a guess, and nobody can tell you what the actual issue is, because it is your database, your input data and only you can find the issue.

我写了一篇文章，解释了如何调试PDO问题.

I wrote an article that explains how to debug your PDO issues.

要调试特定问题，您需要

To debug a particular issue, you need

• 确保同时为PDO和PHP启用了完整的错误报告.确实有帮助，向您显示偶发的印刷错误，拼写错误等
• 仔细检查数据库中的数据和输入以发现差异. bin2hex()函数将有助于显示数据库和输入中的所有不可打印和转换的字符.

• make sure the full error reporting is enabled for both PDO and PHP. It really helps, showing you occasional typographic errors, spelling errors and the such
• scrutinize both the data in the database and the input to find the difference. bin2hex() function would help, revealing all non-printable and converted characters, in both database and the input.

还有一点，但还是非常重要:您准备好的语句是货物崇拜代码， 什么也不保护.这是必须的方式:

On a side note, but very important nevertheless: your prepared statement is a cargo cult code that protects nothing. Here is how it must be:

$sql = 'SELECT count(*) FROM inbox WHERE uid = ? AND from_email = ?'; 
$result = $link->prepare($sql); 
$result->execute([$email_number,$email_f]); 
$number_of_rows = $result->fetchColumn(); 

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