mysqli_ * somemethod *（）_ expect参数

Question

First of all, I was googling it for over 4 hours. Found dozen of similar questions even here on stackoverflow, but I really couldnt find the solution. So thats why im writing new question.. im pretty much a newbie, and i really tried everything I could on my own and with the answers I found here, but nothing seems to be working. Btw, sorry for my broken english..

so here are my errors when i try to submit my new user registration inputs to the database:

Warning: mysqli_query() expects parameter 1 to be mysqli, null given in C:\xampp\htdocs\epo\insert.php on line 17

Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, null given in C:\xampp\htdocs\epo\insert.php on line 18

Warning: mysqli_real_escape_string() expects parameter 1 to be mysqli, null given in C:\xampp\htdocs\epo\insert.php on line 28

Warning: mysqli_real_escape_string() expects parameter 1 to be mysqli, null given in C:\xampp\htdocs\epo\insert.php on line 29

Warning: mysqli_real_escape_string() expects parameter 1 to be mysqli, null given in C:\xampp\htdocs\epo\insert.php on line 30

Warning: mysqli_real_escape_string() expects parameter 1 to be mysqli, null given in C:\xampp\htdocs\epo\insert.php on line 31

Warning: mysqli_query() expects parameter 1 to be mysqli, null given in C:\xampp\htdocs\epo\insert.php on line 36

Warning: mysqli_error() expects parameter 1 to be mysqli, null given in C:\xampp\htdocs\epo\insert.php on line 39
Neuspesno upisivanje u bazu podataka!

here is the db connection code (konekcija.php) :

<?php
ob_start();


if(!isset($_SESSION)){
    session_start();
}


$host = 'localhost';
$user = 'root';
$pass = '';
$db_name = 'epo';

$connection = mysqli_connect($host, $user, $pass, $db_name);

if(!$connection){
    die("CONNECTION TO DB FAILED. " . mysqli_error($connection));
}


?>

here's the registration form (reg.php) file :

<?php include("insert.php"); ?>

<?php include("index.php");?>

   <div class="container">
    <div class="row" style="text-align:center;">
        <h3>Registarcija korisnika za EPO sistem</h3>
    </div>

    <div class="row registracija">
       <div class="row">
           <h3>Dobrodosli, molimo Vas, popunite polja kako biste se registrovali.</h3>
       </div>

        <form action="" method="post" class="form-horizontal">


            <?php echo $errordanger; ?> 
            <?php echo $uspehreg; ?> 


            <div class="row form-group inputgrp">
                <label for="" class="col-sm-2">Ime: </label>
                <div class="col-sm-10">
                   <input type="text" name="ime" id="ime" class="form-control">
                </div>
            </div>

        <form action="" method="post" class="form-horizontal">

            <div class="row form-group inputgrp">
                <label for="" class="col-sm-2">Prezime: </label>
                <div class="col-sm-10">
                   <input type="text" name="prezime" id="prezime" class="form-control">
                </div>
            </div>


        <form action="" method="post" class="form-horizontal">

            <div class="row form-group inputgrp">
                <label for="" class="col-sm-2">E-mail: </label>
                <div class="col-sm-10">
                   <input type="text" name="email" id="email" class="form-control">
                </div>
            </div>


        <form action="" method="post" class="form-horizontal">

            <div class="row form-group inputgrp">
                <label for="" class="col-sm-2">Sifra: </label>
                <div class="col-sm-10">
                   <input type="password" name="password" id="password" class="form-control">
                </div>
            </div>

        <form action="" method="post" class="form-horizontal">

            <div class="row form-group" style="margin: 0px 10px 20px 10px">
                <div class="col-xs-12">
                   <input type="submit" name="submit" id="submit" value="Registruj se" class="form-control">
                </div>
            </div>

        </form>

    </div>




</div>

and here's the insert script (insert.php) :

<?php
    global $connection;
    global $errordanger, $uspehreg;

    $fname = $lname = $email = $password = "";


    if(isset($_POST['submit'])){
        $ime = $_POST['ime'];
        $prezime = $_POST['prezime'];
        $email = $_POST['email'];
        $passw = $_POST['password'];

        //Provera da li korisnik vec postoji


        $sql_query = mysqli_query($connection, "SELECT * FROM signup WHERE email = '{$email}' ");
        $count = mysqli_num_rows($sql_query);


        if($count > 0){

            $errordanger = "<div class='alert alert-danger' role='alert'>
             Korisnik sa tom email adresom vec postoji!
            </div>";
        }else{

            $fname = mysqli_real_escape_string($connection, $ime);
            $lname = mysqli_real_escape_string($connection, $prezime);
            $email = mysqli_real_escape_string($connection, $email);
            $password = mysqli_real_escape_string($connection, $passw);


        $sql = "INSERT INTO signup(email, ime, prezime, password, date_time) VALUES ('{$email}' , '{$ime}', '{$prezime}', '{$passw}', now()) ";

        $query = mysqli_query($connection, $sql);

        if(!$query){
            die(" Neuspesno upisivanje u bazu podataka! " . mysqli_error($connection));

        }else{
            $uspehreg = "<div class='alert alert-success'>
  <strong>Uspesno ste se registrovali!</strong> Indicates a successful or positive action.
</div>";

      }    

    }
 }

?>

Answer 1

Try to Change the SQL QUERY in insert.php in

$sql_query=mysqli_query($connection, "SELECT * FROM signup WHERE email = '$email' ") ;