Refining PDO results from MySQL database with Text Box - php

Question

I'm currently retrieving data from a MySQL database using PDO. I'm using a foreach to display the data onto a page, and wish for the user to be able to enter a search term into a input field, hit the submit button, and then only results who's title contains the search term are returned.
Here is my current code:
file_functions.php - Where the SQL query function is located
function getbycategory($category, $limit){
global $db;
if (isset($category) AND $category != "all") {
$sm = $db->prepare ("SELECT * FROM parts WHERE main_category = :category");
$sm->bindParam(':category', $category, PDO::PARAM_INT);
} else {
$sm = $db->prepare ("SELECT * FROM parts");
}
$sm->execute();
return $sm->fetchAll();
}
files.php - Where the results are displayed
$files = getbycategory($_GET['filter']);
foreach($files as $file){
echo'<div class="col-lg-" id="file-'.$file['id'].'">
<div class="file-list-item first" id="">
<img class="file-image" height="120px" width="180px" src="'.$file['image_url'].'" />
<div class="file-text">
<h3><strong>'.$file['name'].'</strong></h3>
Submitted by: '.$file['submitter'].'<br/>
Author: '.$file['author'].'<br />
Category: '.ucfirst($file['subcategory']).'<br />
Description: '.substr($file['description'],0,45).'...
</div>
<div class="download">
<a target="_blank" href="'.$file['download_url'].'" class="btn-success btn btn-default">Download</a>
Report as Broken<br /><br />';
if($file['is_broken']){
echo '<span class="broken"><i data-toggle="tooltip" data-placement="left" id="broken" title="This file has been reported as broken and is awaiting review." class="fa fa-warning fa-2x"></i></span>';
}
echo '
</div>
</div>
</div>';
};
?>
Below is the form used to refine the results. Currently the filter dropdown menu works for the filter, but the search term does not. This is what I wish to implement
<form method="get">
<select name="filter">
<option <?php if($_GET['filter'] == "all" OR !isset($_GET['filter'])){echo 'selected';} ?> value="all">View All Files</option>
<option <?php if($_GET['filter'] == "1") {echo 'selected';} ?> value="1">View Vehicles Only</option>
<option <?php if($_GET['filter'] == "2") {echo 'selected';} ?> value="2">View Lighting Equiptment</option>
</select>
<input type="submit" value="Filter Results"/><br /><br />
<input type="text" name="search" placeholder="Enter a search term" />
<input type="submit" value="Search Results"/>
</form>
To summarise, I wish to use the text field in the bottom snippet of code to refine the results displayed in files.php by comparing their title to the search term.
I wish to compare the search term to the $file['name'].
Many thanks.

Answer 1

Ok, let me step you through it using a simple LIKE comparison...
First, the method signature. Globals are a bad idea so we'll include the PDO instance
function getbycategory(PDO $db, $category = null, $search = null, $limit = null)
Now, build the query and collect parameters as you go.
$params = [];
$where = [];
if ($category !== null) {
$where[] = 'main_category = :category';
$params[':category'] = [
'val' => (int) $category,
'type' => PDO::PARAM_INT
];
}
if ($search !== null) {
$where[] = "LOWER(`name`) LIKE CONCAT('%', LOWER(:search), '%')";
$params[':search'] = [
'val' => (string) $search,
'type' => PDO::PARAM_STR
];
}
$query = sprintf('SELECT * FROM `parts` %s', implode(' AND ', $where));
if ($limit !== null) {
$query .= ' LIMIT :limit';
$params[':limit'] = [
'val' => (int) $limit,
'type' => PDO::PARAM_INT
];
}
$stmt = $db->prepare($query);
foreach ($params as $key => $param) {
// use bindValue to avoid problems with variable references in the loop
// see http://stackoverflow.com/questions/4174524/binding-params-for-pdo-statement-inside-a-loop
$stmt->bindValue($key, $param['val'], $param['type']);
}
$stmt->execute();
return $stmt->fetchAll(PDO::FETCH_ASSOC);