Use php/MySQL result in new query - php

Question

I've searched around and haven't found anything similar, but it sounds like it should be pretty easy...
I have a search query that searches for a specific userID and displays that information for that user. However, I have one field (let's call it "favorite color" for this example) that will need to be manually updated frequently. So, I want to Search by userID, display the results, somehow re-use the original userID, and update the "favorite color" by the user entry. The part I can't figure out yet is how to store/re-use the userID.
The only way I can get it to work is ->
Search for userID, display results and also populate two new text form fields with original userID as well as "favorite color" to be submitted again by a new UPDATE query. But I don't want the userID to be a text form field, I just want to store the variable use it again.
Does that make sense? =)
Here is a sample of my current code. BTW, it works 100% this way right now, just need to figure out how to store the variable instead of using it again in a text box where I submit the UPDATE query.
<div class="searchBox">
<form method="POST" name="search" action="filter-update.php" class="form-wrapper cf">
<input type="text" name="querySearch" placeholder="User ID" required>
<button type="submit">Search</button>
</form>
</div>
<div id="results">
<?php
if (isset($_POST['querySearch'])){
$query = $_POST['querySearch'];
$min_length = 8;
if(strlen($query) >= $min_length){
$query = htmlspecialchars($query);
$query = mysqli_real_escape_string($conn, $query);
$sql = "SELECT * FROM sites WHERE userID = $query";
$raw_results = mysqli_query ($conn, $sql) or die ('error getting data from database');
if(mysqli_num_rows($raw_results) > 0){
while ($results = mysqli_fetch_array($raw_results)) {
echo "<div class='title'>User ID:</div><div class='info'>".$results['userID']."</div>";
echo "<div class='title'>Name:</div><div class='info'>".$results['name']."</div>";
echo "<div class='title'>Fav Color:</div><div class='info'>".$results['favColor']."</div>";
$userID = $results['userID'];
}
}
else { // if there is no matching rows do following
echo "No results";
}
}
else{ // if query length is less than minimum
echo "<br>Minimum length is ".$min_length;
}
}
?>
</div>
<div class="searchBox">
<form method="POST" name="filterUpdate" action="filter-update.php" class="form-wrapper cf">
<input type="text" name="UserID" value="<?php echo $userID;?>" required><br><br><br>
<input type="text" name="favColor" placeholder="New favColor here..." required>
<button type="submit">Update</button>
</form>
</div>
<div id="results">
<?php
if (isset($_POST['filterUpdate'])){
$queryFilter = $_POST['filterUpdate'];
$userID = $_POST['userID'];
$min_length = 1;
if(strlen($queryFilter) >= $min_length){
$queryFilter = htmlspecialchars($queryFilter);
$userID = htmlspecialchars($userID);
$queryFilter = mysqli_real_escape_string($conn, $queryFilter);
$userID = mysqli_real_escape_string($conn, $userID);
$sql = "UPDATE sites SET favColor = '$queryFilter' WHERE userID = '$userID'";
$raw_results = mysqli_query ($conn, $sql) or die ('error getting data from database');
}
else{ // if query length is less than minimum
echo "<br>Minimum length is ".$min_length;
}
}
?>
</div>

Answer 1

You can try either of this:
Hidden Field:
<input type="hidden" name="UserID" value="<?php echo $userID;?>">
Session:
$_SESSION['userID'] = $userID;
Don't know if this will work, but you can put the $userID above all the codes(like a global var).