How do I check 2 mysql tables at the same time?

$sql = "SELECT * FROM 'zzzz_1_post' WHERE POST_autor=1;

but I also want to get

$sql = "SELECT * FROM 'zzzz_0_post' WHERE POST_autor=0;

I'm doing it in a while, but I do not know how to combine the 2 tables at once.

My tables:

while($row = $resultado->fetch_assoc()) {//COMPROBAR POST
    $AMIGO_USUARIO_RED = $row['FRIEND_usuario'];
     $sql = "SELECT * FROM 'zzzz_".$row['FRIEND_usuario']."_post' WHERE POST_autor=".$row['FRIEND_usuario'];
    $resultado = $mysqli->query($sql);
    if(!$resultado = $mysqli->query($sql)) {
        echo "La consulta falló ";
        echo "Error: Lo sentimos, error a al conectarse, reinicie la pagina.";
        echo "Query: " . $sql . "\n";
        echo "Errno: " . $mysqli->errno . "\n";
        echo "Error: " . $mysqli->error . "\n";
        exit;
    }

    while($row = $resultado->fetch_assoc()) {//MOSTRAR LOS POST
    ?>
        <article class="post_view_public">
          <div class="post_view_loading">
             <i class="fa fa-spinner fa-pulse fa-3x fa-fw"></i>
                <span class="sr-only">Cargando...</span>
          </div>
           <script type="text/javascript">
               function ocultar(){
                document.getElementById('post_view_loading').classList.add = "mostrar_loading_post" ;
                document.getElementById('post_view_public').classList.add = "ocultar_objetos";
                }
            </script>

            <div id="post_view_public">
            <div class="up">
            <?php
                    $sql2 = "SELECT * FROM 'a_redcdark_social' WHERE id_usuarios=".$AMIGO_USUARIO_RED;
                    $resultado2 = $mysqli->query($sql2);
                    if(!$resultado2 = $mysqli->query($sql2)) {
                        echo "La consulta falló ";
                        echo "Error: Lo sentimos, error a al conectarse, reinicie la pagina.";
                        echo "Query: " . $sql . "\n";
                        echo "Errno: " . $mysqli->errno . "\n";
                        echo "Error: " . $mysqli->error . "\n";
                        exit;
                    }

                    // No hay datos en esa consulta
                    if ($resultado2->num_rows === 0) {
                        echo "No Tienes amigos agregadoss";
                    }

                     while($row2 = $resultado2->fetch_assoc()) {

                         ?>
                <a href="?page=profile&id=<?php echo $row2['id_usuarios'];?>">
                    <img src="<?php echo $row2['RED_imagen_perfil'];?>" alt="user">
                    <h3><?php echo $row2['RED_nombre']; ?> <?php echo $row2['RED_apellido']; ?></h3>
                </a>

                <?php
                     }
                ?>
                <i class="fa fa-ellipsis-h"></i>
            </div>

            <div class="center" style="background:<?php echo $row['POST_background']?>">
        <?php

        if($row['POST_imagen'] == ""){
            echo $row['POST_texto'];
        }else{
            echo $row['POST_texto'];
            ?>

            <div class="imagen"><img src="<?php echo $row['POST_imagen'];?>" alt=""></div>
        <?php
        }
        ?>
            </div>
            <div class="downcent">
               <i class="fa fa-thumbs-o-up"> Like</i>
                <i class="fa fa-globe"></i>
                <i class="fa fa-ellipsis-v"></i>
            </div>
            <div class="down">
                <img class="comentuser" src="images/example/myuser.jpg" alt=""><span class="info">Usuario</span>

                <input type="text" placeholder="Comenta esta publicación">

                <i class="fa fa-smile-o"></i>
                <i>:v</i>
                <i class="fa fa-camera"></i>
                <i class="fa fa-ellipsis-v"></i>
            </div>
            </div>
            <script type="text/javascript">
               function mostrar(){
                    document.getElementById('post_view_loading').classList.remove = "mostrar_loading_post" ;
                   document.getElementById('post_view_loading').classList.add = "ocultar_objetos" ;
                   document.getElementById('post_view_public').classList.remove = "ocultar_objetos";
                    document.getElementById('post_view_public').classList.add = "mostrar_objetos";


                }
            </script>
        </article>
            <?php
    }

}//fin while 1

I want you to show the tables of the users (2)