Errors in mysqli, expected parameters [duplicate]

The following errors are appearing:

  

Warning: mysqli_query () expects at least 2 parameters, 1 given in C: \ xampp \ htdocs \ network \ profile.php on line 25

     

Warning: mysqli_fetch_assoc () expects parameter 1 to be mysqli_result, null given in C: \ xampp \ htdocs \ network \ profile.php on line 26

     

Warning: mysqli_query () expects at least 2 parameters, 1 given in C: \ xampp \ htdocs \ network \ profile.php on line 31

     

Warning: mysqli_error () expects exactly 1 parameter, 0 given in C: \ xampp \ htdocs \ network \ profile.php on line 31

My code:

<?php
include("header.php");

$id = $_GET["id"];
$saberr = mysqli_query($connect, "SELECT * FROM users WHERE id='$id'");
$saber = mysqli_fetch_assoc($saberr);
$email = $saber["email"];

if ($email==$login_cookie) {
    header("Location: myprofile.php");
}

$pubs = mysqli_query($connect, "SELECT * FROM pubs WHERE user='$email' ORDER BY id desc");

if (isset($_POST['add'])) {
    add();
}

function add(){
    $login_cookie = $_COOKIE['login'];
    if (!isset($login_cookie)) {
        header("Location: login.php");
    }
    $id = $_GET['id'];
    $saberr = mysqli_query("SELECT * FROM users WHERE id='$id'");
    $saber = mysqli_fetch_assoc($saberr);
    $email = $saber['email'];
    $data = date("Y/m/d");

    $ins = "INSERT INTO amizades (de, para, data) VALUES ('$login_cookie', '$email', '$data')";
    $conf = mysqli_query($ins) or die(mysqli_error());
    if ($conf) {
        header("Location: profile.php?id=".$id);
    }else{
        echo "<h3>Erro ao enviar pedido...</h3>";
    }
}

if (isset($_POST['cancelar'])) {
    cancel();
}