How to use tags in MySQL and PHP

I'm creating a website and would like to know how I can use tags with MySQL and PHP.

I have two tables: produtos and informacao .

In the informacao table I have a field called related products where I will put products separated by commas, how can I then get those names without the commas so I can do a search with each of them?

I have the following code:

<?
$explode = explode(',',$relacionados);
foreach($explode as $nome){

    $result = $connection -> query("select * from produtos where titulo='$nome' and linguagem='$lang'");
    while($row = $result -> fetch_array(MYSQLI_ASSOC)){
        $id = $row['id'];
        $titulo = $row['titulo'];
        $resumo = $row['resumo'];
        $imagem = $row['imagem'];
        $categoria = $row['tags'];
?>

        <div class="grid_3">
            <div class="box2 wrap1 wow fadeInLeft" data-wow-delay="0.1s">
                <a href="verproduto.php?id=<?=$id?>&lang=<?=$lang?>" id="produto"><img class="first" src="<?=$imagem?>" alt=""/></a>
                <div class="caption bggreen equal">
                    <h6 class="text_3 colorblue">
                        <a href="verproduto.php?id=<?=$id?>&lang=<?=$lang?>"><?=$titulo?></a>
                    </h6>
                    <br>
                    <p class="colorwhite">
                    <?=$resumo?>
                    </p>
                </div>
            </div>
        </div>
<?
}}
?>
</div>
<? 
$result -> free();
?>

With this code I was only able to print the second related product that was where string made explode , I need to print all products, not where it starts.