如何使用strpos将数据库中的常见垃圾邮件字段与表单提交相匹配？

I get a few spam responses to my web contact form and I've used these to build up a list of fields to filter on. My plan was to compare - using strpos - each field against the text field submitted by the user and, if there's a match, redirect that mail response.

For whatever reason, the code I'm trying just doesn't seem to hit a match; what am I missing?

// Query list of spam fields
    $sqlSpam= "SELECT * FROM tblspamfilter";  
    $rstSpam= mysqli_query($db, $sqlSpam);

// Search for key in the notes field passed by the web form 
    while ($rowSpam=mysqli_fetch_assoc($rstSpam)) {
        $Key= $rowSpam['Key'];
        if (strpos($notes, $Key) === false) {
            $spam=0;
            } else {
            $spam++;
            }
        }

if ($spam==0) {
    // send the mail...
    } else {
    // not today Mr spammer
    }

It worked OK as a static spam key, but noyt now that I've added teh database element. Nothing I try in my form submission field (exact match, part match etc. ) matches as a spam event and all the mail gets through. I'm quite new to php so I assume I'm missing something in the way it compares the data from the table?

Edit: I have the following fields in my spam table:

| idKey | Key | 
| 1 | jnl.io | 
| 2 | drive.google.com | 
| 3 | casinogorilla.com | 
| 4 | www.talkwithcustomer.com | 
| 5 | sexy | 
| 6 | profitable database of email addresses | 
| 7 | My name is Roy | 
| 8 | Sexy girls |

And using this code:

$spamWords = mysqli_fetch_assoc($rstSpam);
$spam = 0;
foreach ($spamWords as $spamWord) {
    if (strpos($notes, $spamWord) !== false) {
        $spam++;
    }
}

I get a match for jnl.io, drive.google.com but not for www.talkwithcustomer.com, sexy etc. I don't see a pattern for it at all. Is there a size limit? Is strpos the wrong technique?

Working Code The following is now working; not sure exactly what fixed it, but there was an odd collation for the table which I have replaced with utf8_general_ci and this, amongst the other suggestions has got it testing OK. Many thanks for looking in.

// Check the notes field for any likely spam indicators
    $spam=0;
    while ($rowSpam=mysqli_fetch_assoc($rstSpam)) {
        $Key= $rowSpam['Key'];
        if (strpos($notes, $Key) !== false) {
            $spam++;
            }
        }

Example code, where you can see your approach vs. the right approach to this problem... https://3v4l.org/Yidr1

<?php

$spamWords = ['blah', 'nah', 'hah', 'spam', 'spamm'];

$spamMessage = 'Here we go blah blah blah';

// this is the way you do this
$spam = 0;
foreach ($spamWords as $spamWord) {
    if (strpos($spamMessage, $spamWord) === false) {
        echo 'This keyword aint here, previous value - ' . $spam . PHP_EOL;
        $spam = 0;
    } else {
        $spam++;
        echo 'I am spam' . PHP_EOL;
    }
}

if ($spam === 0) {
    echo 'not spam' . PHP_EOL;
} else {
    echo 'spam' . PHP_EOL;
}
// well obviously, you will echo 'spam' only if lastword from your spam-words will be present
// so you need to keep your variable
echo 'Right approach' . PHP_EOL;
$spam = 0;
foreach ($spamWords as $spamWord) {
    if (strpos($spamMessage, $spamWord) !== false) {
        $spam++;
    }
}
// now works as expected
if ($spam === 0) {
    echo 'not spam';
} else {
    echo 'spam';
}