PHP - Mysqli_num_rows

Hey guys,

here's the script:



<?php



require("header.php");



$sql = "SELECT entries.*, categories.cat FROM entries, categories

    WHERE entries.cat_id = categories.id

    ORDER by dateposted DESC

    LIMIT 1;";

$result = mysqli_query($db, $sql);

$row = mysqli_fetch_assoc($result);



echo "<p><h2><a href='viewentry.php?id=".$row['id']."'>'".$row['subject']."</a></h2><br /></p>";

echo "<p>"."<i>In <a href='viewcat.php?id=" . $row['cat_id']."'>'" . $row['cat']."</a> - Posted on " . date("D jS F Y g.iA", strtotime($row['dateposted']))."</i></p>";

echo "<p>";

echo nl2br($row['body']);

echo "</p>";



echo "<p>";



$commsql = "SELECT name FROM comments WEHRE blog_id = " .$row['id']."ORDER BY dateposted;";

$commresult = mysqli_query($db, $commsql);

$numrows_comm = mysqli_num_rows($commresult);



if($numrows_comm == 0){



    echo "<p>No comments.</p>";



} else {

    echo "(<b>".$numrows_com."</b>)comments: ";

    $i = 1;

    while($commrow = mysqli_fetch_assoc($commresult)){

    

        echo "<a href='viewentry.php?id=".$row['id']."#comment".$i."'>'".$commrow['name']."</a>";

        $i++;

    

    }



}

echo "</p>";



require("footer.php");





?>



The error turns out to be Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given in C:\xampp\htdocs\Book\index.php on line 22

why is that?

trying to figure this problem out. sucks being a newbie maybe i will gain enough knowledge to be able to help out others in the near future.
Code: [Select]
<?php
session_start();

$DBConnect = @mysqli_connect("localhost", "**********", "**********")
Or die("<p>Unable to connect to the database server.</p>"
. "<p>Error code " . mysqli_connect_errno()
. ": " . mysqli_connect_error()) . "</p>";
$DBName = "skyward_aviation";
@mysqli_select_db($DBConnect, $DBName)
Or die("<p>Unable to select the database.</p>"
. "<p>Error code " . mysqli_errno($DBConnect)
. ": " . mysqli_error($DBConnect)) . "</p>";

$CustomerName = "";
if (isset($_COOKIE['customerName']))
$CustomerName = $_COOKIE['customerName'];

$TableName = "mileage";
$Mileage = 0;
$SQLstring = "SELECT SUM(mileage) FROM $TableName WHERE
flyerID='{$_SESSION['flyerID']}";
$QueryResult = @mysqli_query($DBConnect, $SQLstring);
if (mysqli_num_rows($QueryResult) > 0) {
$Row = mysqli_fetch_row($QueryResult);
$Mileage = number_format($Row[0], 0) ;
mysqli_free_result($QueryResult);
}

mysqli_close($DBConnect);

?>

i know its a simple stupid error but cant remember nor figure it out. HERES THE ERROR

Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given in C:\xampp\htdocs\PHP_Projects\Chapter.10\FrequentFlyerClub.php on line 23

This is the form:

Code: [Select]
<form id="submit_form" method="post" action="">

       
<label for="knuffix_category"><h4>Choose a category</h4></label><br />
     
        <?php 
        require_once ($sort_category_func);
        $switch = 0;
        sort_category ($switch); 
        ?>


<br /><br />

       
        <label for="contribution_description"><h4>Enter your description here</h4></label><br />
        <textarea maxlength="150" type="text" name="contribution_description" value=""></textarea><br />
       
       
       
       
<label for="contribution"><h4>Enter your contribution here</h4></label><br />
<textarea maxlength="300" type="text" name="contribution" value=""></textarea><br />

       
       
<input type="submit" name="submit" value="Contribute" />
       
       
</form>



<?php
    include($submit_script);
?>



And this is the script:

Code: [Select]
<?php
if (isset($_POST['submit'])){

if (isset($user_name)) {
 // Connect to the database 
  $dbc = mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);
  
                  
                  
// Grab the score data from the POST
                
//$knuffix_name = strip_tags(trim($_POST['knuffix_name']));

                $contribution_name = uniqid();
                
                if (!empty($_POST['contribution_description']))
                    $contribution_description = $_POST['contribution_description'];
               // if (!empty($_POST['knuffix_contribution']))
                    $contribution = $_POST['contribution'];
                // if (!empty($_POST['cat'])) {
                    $contribution_category = strip_tags(trim($_POST['cat']));
               // }
                
                
                  // Check if the fields and variables are empty
                
  if (!empty($contribution_category) && !empty($contribution)) {
 
                      
                      
                      
                      // Check if the submission exists twice in the whole database
                      
                      $query_get = "SELECT contribution FROM con WHERE = '{$contribution}'";
                      
                      $query_run = mysqli_query($dbc, $query_get);
                      
                      $num_rows = mysqli_num_rows($query_run);
                      

                   
                      
                      if ($num_rows == 0) {

                      
                          
                          
                          
                          // Write the data into the database
                          
  $query = sprintf("INSERT INTO con (user_id, name, contribution, category, contribution_date, description) VALUES ('$user_id', '%s', '%s', '%s', now(), '%s')",
mysqli_real_escape_string($dbc, $contribution_name),
mysqli_real_escape_string($dbc, $contribution),
mysqli_real_escape_string($dbc, $contribution_category),
                                        mysqli_real_escape_string($dbc, $contribution_description));
 
                          
                            mysqli_query($dbc, $query) or die (mysqli_error($dbc));

                            mysqli_close($dbc);
   
  /* Set a cookie (later) to prevent duplicate submissions */
  // redirect the page to prevent duplicate submissions
// header ('Location: redirect.php');
echo 'Contributing was successful.';   
 
                                
                          
                                
                                
                      } else {
                          
                          
                          echo "This contribution already exists in the database. 
                              To keep this place clean we do not allow duplicate submissions.";
                          
                          
                          
                      }
                       
                      
                      
                      } else {



                            echo "Please enter all of the information to add your contribution.";



                            }

                        
                        
                      } else {



                            echo "You have to be signed-in to do a contribution.";



                            }
    }
?>


And this is the error message:

Code: [Select]
Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given in C:\xampp\htdocs\php_projects\myproject\controller\contribution\submit_script.php on line 38


As the error message states it is not becoming a result, and I do not see where the problem lies, everything looks right to me. Does somebody else see a mistake in there?

My code looks as follows:


include('connectvars.php');

/* REGISTER FORM */
// check if submit button has been clicked
if (isset($_POST['submit_signup'])) {

// process and assign variables after post submit button has been clicked
$user_email  = strip_tags(trim($_POST['email']));
$firstname  = strip_tags(trim($_POST['firstname']));
$lastname  = strip_tags(trim($_POST['lastname']));
$nickname  = strip_tags(trim($_POST['nickname']));
$password  = $_POST['password'];
$repassword  = $_POST['repassword'];
$dob  = $_POST['dob'];
$find_us_question  = strip_tags(trim($_POST['find_us_question']));

// connect to database
$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);

$check_query = "SELECT * FROM users WHERE nickname = '$nickname'";

$check_connect  = mysqli_query($dbc, $check_query);

$check_count =  mysqli_num_rows($check_connect);

echo $check_count;

die();



It's a register (sign up) page, and it's the beginning of the script, the rest of the script is just checking if all fields are a empty and if the input is in the allowed character length etc. I could it off at die(); because the rest doesn't matter.

I want the script to check if the username already exists in the database, so I want mysqli_num_rows to tell me how many rows are already there with the same username, and then I want to continue doing an if statement saying


if ($check_count != 0) {
echo "Username already exists!"
}


But the mysqli_num_rows doesn't even print out how many rows there are availible, it gives me an error saying:

Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given in...


The num_rows function worked in the login script the same way, but for some reason it's not working in the register script.

Any ideas, what I'm doing wrong?

For testing purposes I just want it to print me "1" when I'm entering a username that's already in the database.

Hi all,

I have received a warning message, which it still puzzles me. I suspect it might be my inner join command, which I have coded it wrongly?

Line 37 refers to this line -  if (mysqli_num_rows($data) == 1) {

Do you guys have any idea? Thanks

Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given in D:\inetpub\vhosts\123.com\http\viewprofile.php on line 37

Code: [Select]
<?php
  // Connect to the database
  $dbc = mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);

  $query = "SELECT tp.name, tp.nric, tp.gender, tp.race_id, r.race_name AS race" .
        "FROM tutor_profile AS tp " .
        "INNER JOIN race AS r USING (race_id) " .
"WHERE tutor_id = '" . $_GET['tutor_id'] . "'";
  
  $data = mysqli_query($dbc, $query);

  if (mysqli_num_rows($data) == 1) {
    // The user row was found so display the user data
    $row = mysqli_fetch_array($data);
    echo '<table>';
    if (!empty($row['name'])) {
      echo '<tr><td class="label">Name:</td><td>' . $row['name'] . '</td></tr>';
    }
    if (!empty($row['nric'])) {
      echo '<tr><td class="label">NRIC:</td><td>' . $row['nric'] . '</td></tr>';
    }
    if (!empty($row['last_name'])) {
      echo '<tr><td class="label">Last name:</td><td>' . $row['last_name'] . '</td></tr>';
    }
    if (!empty($row['gender'])) {
      echo '<tr><td class="label">Gender:</td><td>';
      if ($row['gender'] == 'M') {
        echo 'Male';
      }
      if ($row['gender'] == 'F') {
        echo 'Female';
      }
      echo '</td></tr>';
    }
if (!empty($row['race'])) {
      echo '<tr><td class="label">Race:</td><td>' . $row['race'] . '</td></tr>';
    }

    echo '</table>'; //End of Table

    echo '<p>Would you like to <a href="editprofile.php?tutor_id=' . $_GET['tutor_id'] . '">edit your 

  } // End of check for a single row of user results
  else {
    echo '<p class="error">There was a problem accessing your profile.</p>';
  }

  mysqli_close($dbc);
?>