I can't get MAX(id) into variabele with + 1

Tissle · July 1, 2010

Hello,

I want to get the max id of the table pages. I tried a lot of things but nothing seems to work

The code i now use is :

$select_maxid = mysql_query("SELECT MAX(id) FROM `pages`");

$row1 = mysql_fetch_row($select_maxid, MYSQL_NUM);

$max_id = $row1[0];

echo $max_id;

but i gives my no result.

can someone please help me out with this?

trq · July 1, 2010

Have you tried checking your query actually succeeds before using any result it produces? Any debugging at all? What does mysql_error() have to say?

Tissle · July 1, 2010

First of all thanks for the quick reply

When i type this:

$select_maxid = mysql_query("SELECT MAX(id) FROM `pages`"); or die(mysql_error());

$row1 = mysql_fetch_row($select_maxid, MYSQL_NUM);

$max_id = $row1[0];

echo $max_id;

it gives me a blank page

I've tried the query in phpmyadmin and there it works.

so any suggestions ?

Ruzzas · July 1, 2010

make sure your mysql is connected and logged in

$select_maxid = mysql_query("SELECT MAX(id) FROM `pages`"); or die(mysql_error());
if($row1 = mysql_fetch_row($select_maxid, MYSQL_NUM)){
    $max_id = $row1[0];
    echo $max_id;
}else{
    $Error = mysql_error();
    echo("Failed: $Error");
}

trq · July 1, 2010

if ($select_maxid = mysql_query("SELECT MAX(id) AS max_id FROM pages")) {
  $row = mysql_fetch_assoc($select_maxid) {
  else $row['max_id'];
} else {
  echo mysql_error();
}

Tissle · July 1, 2010

Thanks i now know what's the failure.

im now using this code

$select_maxid = mysql_query("SELECT MAX(id) FROM `pages`");
			if($row1 = mysql_fetch_row($select_maxid, MYSQL_NUM)){
			    $max_id = $row1[0];
			    echo $max_id;
			}else{
			    $Error = mysql_error();
			    echo("Failed: $Error");
			}

it says: Failed: No database selected.

but at the top of my document i require my connection with the database so how can i solve this problem?

trq · July 1, 2010

Obviously the connection isn't being made.

PS: That code is floored.

Tissle · July 1, 2010

But i use more php in my document wich als require database connection and they work all just fine.

I tried putting the require connection also between those php tags but with no result.

so what can i do to make that connection with the database ?

trq · July 1, 2010

Use the code I posted above and post the exact output.

Tissle · July 1, 2010

When i use you code it shows me a blank page with no error.

trq · July 1, 2010

Hehe... Theres a type in my code. Try this..

if ($select_maxid = mysql_query("SELECT MAX(id) AS max_id FROM pages")) {
  $row = mysql_fetch_assoc($select_maxid) {
  echo $row['max_id'];
} else {
  echo mysql_error();
}

Tissle · July 1, 2010

still blank

trq · July 1, 2010

Your going to need to post all your relevant code. Also, make sure you have error_reporting set to E_ALL and display errors switched on.

Tissle · July 1, 2010

Okey here is my whole document :

<?php require_once '../cms/includes/connection.php'; ?>
<!-- Hier wordt de content en de titel geupdated en als dit gebeurt krijgt de variabele m de waarde van 1 -->
<?php


if(isset($_POST['submit'])){

	$content	= $_POST['content'];
	$title		= $_POST['title'];



	$sql		= "INSERT INTO pages VALUES ('', '$title', '$content', '')";	
	$sql1		= "INSERT INTO nav VALUES ('', '$title', 'index.php?p=$title', '$title')";

	$result		= $conn->query($sql) or die(mysqli_error());
	$result1	= $conn->query($sql1) or die(mysqli_error());

}
?>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
      <html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>
<title>Portfolio Thijs van Emmerik</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<link rel="stylesheet" type="text/css" href="../style/style.css"/>
<link rel="shortcut icon" href="../images/favicon.ico"/>
<!-- TinyMCE --> 
<script type="text/javascript" src="js/tiny_mce/tiny_mce.js"></script> 
<script type="text/javascript"> 
tinyMCE.init({
	// General options
	mode : "textareas",
	theme : "advanced",
	skin : "o2k7",
	skin_variant : "black",
	plugins : "pagebreak,style,table,save,advhr,advimage,advlink,emotions,iespell,insertdatetime,preview,media,searchreplace,print,contextmenu,paste,directionality,fullscreen,noneditable,visualchars,nonbreaking,xhtmlxtras,template,inlinepopups,autosave",

	// Theme options
	theme_advanced_buttons1 : "save,newdocument,|,bold,italic,underline,strikethrough,|,justifyleft,justifycenter,justifyright,justifyfull,|,styleselect,formatselect,fontselect,fontsizeselect",
	theme_advanced_buttons2 : "cut,copy,paste,pastetext,pasteword,|,search,replace,|,bullist,numlist,|,outdent,indent,blockquote,|,undo,redo,|,link,unlink,anchor,image,cleanup,help,code,|,insertdate,inserttime,preview,|,forecolor,backcolor",
	theme_advanced_buttons3 : "tablecontrols,|,hr,removeformat,visualaid,|,sub,sup,|,charmap,emotions,iespell,media,advhr,|,print,|,ltr,rtl,|,fullscreen",
	theme_advanced_buttons4 : "styleprops,|,cite,abbr,acronym,del,ins,|,visualchars,nonbreaking,template,pagebreak,restoredraft",
	theme_advanced_toolbar_location : "top",
	theme_advanced_toolbar_align : "left",
	theme_advanced_statusbar_location : "bottom",
	theme_advanced_resizing : true,

	// Example word content CSS (should be your site CSS) this one removes paragraph margins
	content_css : "css/word.css",

	// Drop lists for link/image/media/template dialogs
	template_external_list_url : "lists/template_list.js",
	external_link_list_url : "lists/link_list.js",
	external_image_list_url : "lists/image_list.js",
	media_external_list_url : "lists/media_list.js",

	// Replace values for the template plugin
	template_replace_values : {
		username : "Some User",
		staffid : "991234"
	}
});
</script> 
<!-- /TinyMCE -->
</head>
<body>
<div id="container">
<div id="header">
	<ul class="nav">
	<!-- Hier wordt het menu uit de database gelezen en gelijk in list items gezet -->
			<?php
			include('../cms/includes/connection.php');
				$page 	= (isset($_GET['p'])) ? $_GET['p'] : "1";
				$sql	= "SELECT id,name,url,title FROM nav";
				$result	= $conn->query($sql) or die(mysqli_error());

				if($result){
					while($row = $result->fetch_object()) {
						echo "<li> <a href='../{$row->url}' title='{$row->title}'>{$row->name}</a> </li>";
					}
				}	
			?>
	</ul>
</div>
<div id="banner">
	<div id="THIJSVANEMMERIK">
	THIJS VAN EMMERIK
	</div>
</div>
<div id="content">
<div class="cmscontent">
<h2>Nieuwe pagina toevoegen</h2>
<br /><br />
<div class="adminlink"><a href="index.php"><-- admin panel</a></div><br /><br />
<form method="post" action="">
	<table border="0" width="700" cellpadding="2">
	<tr>
		<td valign="top"><label for="title">Title:</label></td>
			<td><input type="text" name="title" /> <br /> <br /></td>
	</tr>
	<tr>
		<td valign="top"><label for="content">Content:</label><br /></td>
			<td><textarea class="editpage" name="content"><?php
			if ($select_maxid = mysql_query("SELECT MAX(id) AS max_id FROM pages")) {
				  $row = mysql_fetch_assoc($select_maxid) {
				  echo $row['max_id'];
				} else {
				  echo mysql_error();
				}		
			 ?> </textarea> <br /> <br /></td>
	</tr>
	<tr>
		<td><input type="submit" name="submit" value="aanmaken" /></td>
	</tr>
	</table>
</form>

</div>

</div>

<div id="contentfoot"></div>

    
</div>
</body>
</html>

And i don't know where i can turn error_reporting to E_ALL and display error switched on

trq · July 1, 2010

The rest of your code is using some database abstraction layer, and maybe the mysqli extension. What exactly is within your connection.php file?

Tissle · July 1, 2010

This is exactly what is in my connection.php

<?php
$conn = new MySQLi("localhost", "username", "pass", "db") or die("Er kan geen verbinding worden gemaakt ".mysql_error());

exept for the username pass and db

PFMaBiSmAd · July 1, 2010

Tissle, your code is a mismatch of using mysqli and mysql.

Your connection is creating a mysqli object. You must use mysqli throughout the remainder of your code and in the places were you are using the proper mysqli_error() function you must supply the connection link as a parameter or simply use mysqli OOP instead of procedural function calls.

Your code is probably producing numerous errors do to the mismatch of functions. Are you developing and debugging your code on a system with error_reporting set to E_ALL and display_errors set to ON in your master php.ini so that all the errors php detects will be reported and displayed. You will save a ton of time.

Tissle · July 1, 2010

Thanks for the reply i didn't know that.

How can i make a php.ini with all the errors ON ?

Sorry I'm a noob with php but willing to learn a lot about it.

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I can't get MAX(id) into variabele with + 1

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