Error in PHP code - SQLSTATE [42000] [closed]

I am trying to list the categories and subcategories present in the database but the following error is pointed out:

  

Fatal error: Uncaught exception 'PDOException' with message   'SQLSTATE [42000]: Syntax error or access violation: 1064 You have an   error in your SQL syntax; check the manual that corresponds to your   MariaDB server version for the right syntax to use near   '' store_categories' ORDER BY id DESC 'at line 1' in   C: \ xampp \ htdocs \ lojacurso \ classes \ Site.class.php: 8 Stack trace: # 0   C: \ xampp \ htdocs \ lojacurso \ classes \ Site.class.php (8):   PDOStatement-> Run () # 1   C: \ xampp \ htdocs \ lojacourse \ pages \ category.php (13): Site-> getMenu () # 2   C: \ xampp \ htdocs \ lojacurso \ index.php (20):   include_once ('C: \ xampp \ htdocs ...') # 3 {main} thrown in   C: \ xampp \ htdocs \ lojacurso \ classes \ Site.class.php on line 8

The code is this:

<?php

class Site extends BD{

    public function getMenu(){
        $pegar_categorias = "SELECT * FROM 'loja_categorias' ORDER BY id DESC";
        $executar = self::conn()->prepare($pegar_categorias);
        $executar->execute();

        if ($executar->rowCont() == 0) {
            # não faz nada pois não há categorias
        }else{
            while ($categoria = $executar->fetchObject()) {
                echo '<li><a href="'.PATH.'/categoria/'.$categoria->slug.'">'.$categoria->titulo.'';

                    $pegar_subcategorias = "SELECT * FROM 'loja_subcategorias' WHERE id_cat = ?";
                    $executar_sub = self::conn()->prepare($pegar_subcategorias);
                    $executar_sub->execute(array($categoria->id));
                    if ($executar_sub->rowCont() == 0) {
                        echo '</li>';
                    }else{
                        echo '<ul>';
                        while ($subcategoria == $executar_sub->fetchObject()) {
                            echo '<li><a href=" '.PATH.'/categoria/'.$categoria->slug.'/'.$subcategoria->slug.' ">'.$subcategoria->titulo.'</a></li>';
                        }//termina while subcategoria
                        echo '</ul></li>';

                    }//termina else dos resultados da subcategoria
            }//termina while das categorias
        }//primeiro else
    }//TERMINA FUNÇÃO getMenu

}

?>