Simple Pagination

[Jaan]

Hey there.. It has been a long time since I wrote a tutorial.. but now I thought I'll do it.. So let's start

First we have to connect to our database:

// Connect to your database
$mysql_con = mysql_connect("localhost", "Username", "Password");

// Let's check if there were any errors
if(!$mysql_con){
    
    // If there was ań error, if there was, lets display an error
    die(mysql_error());
    
}

// Select your database
$mysql_db = mysql_select_db("MyDatabase");

// If there were any errors with selecting your database, display an error
if(!$mysql_db){
    
    die(mysql_error());
    
} 

Now we are connected to database.. Let's get our information.
First we need to get our page number:

// If the page wasn't set, lets set $page to number 1 for the first page
if($page == ""){
    
    $page = "1";
    
}else{
    
    // If page is set, lets get it
    $page = $_GET['page'];
    
} 

Now we need to get all messages from database and count them:

// Now lets get all messages from your database
$sql = "SELECT * FROM messages";
$query = mysql_query($sql);

// Lets count all messages
$num = mysql_num_rows($query); 

When these things are done.. lets set our numbers:

// Lets set how many messages we want to display
$per_page = "10";

// Now we must calculate the last page
$last_page = ceil($num/$per_page);

// And set the first page
$first_page = "1"; 

Now it's time for "Next" , "Previous" First and last page.. :

// Here we are making the "First page" link
echo "<a href='?page=".$first_page."'>First page</a> ";

// If page is 1 then remove link from "Previous" word
if($page == $first_page){
    
    echo "Previous ";
    
}else{
    
    if(!isset($page)){
        
        echo "Previous ";
        
    }else{
        
        // But if page is set and it's not 1.. Lets add link to previous word to take us back by one page
        $previous = $page-1;
        echo "<a href='?page=".$previous."'>Previous</a> ";
    
    }
    
}

// If the page is last page.. lets remove "Next" link
if($page == $last_page){
    
    echo "Next ";    
    
}else{
    
    // If page is not set or it is set and it's not the last page.. lets add link to this word so we can go to the next page
    if(!isset($page)){
        
        $next = $first_page+1;
        echo "<a href='?page=".$next."'>Next</a> ";
        
    }else{
    
        $next = $page+1;
        echo "<a href='?page=".$next."'>Next</a> ";
    
    }
    
}

// And now lets add the "Last page" link
echo "<a href='?page=".$last_page."'>Last page</a>"; 

Now lets do some math and get our messages :

// Math.. It gets us the start number of message that will be displayed
$start = ($page-1)*$per_page;

// Now lets set the limit for our query
$limit = "LIMIT $start, $per_page";

// It's time for getting our messages
$sql = "SELECT * FROM messages $limit";
$query = mysql_query($sql);

echo "<br /><br />";

// And lets display our messages
while($row = mysql_fetch_array($query) or die(mysql_error())){
    
    echo $row['message']."<br />";
    
} 

Voila.. it wasn't that hard right ?

Here's the full code with comments:

<?php

// Connect to your database
$mysql_con = mysql_connect("localhost", "Username", "Password");

// Let's check if there were any errors
if(!$mysql_con){
    
    // If there was ań error, if there was, let's display an error
    die(mysql_error());
    
}

// Select your database
$mysql_db = mysql_select_db("MyDatabase");

// If there were any errors with selecting your database, display an error
if(!$mysql_db){
    
    die(mysql_error());
    
}

// If the page wasn't set, lets set $page to number 1 for the first page
if($page == ""){
    
    $page = "1";
    
}else{
    
    // If page is set, let's get it
    $page = $_GET['page'];
    
}

// Now lets get all messages from your database
$sql = "SELECT * FROM messages";
$query = mysql_query($sql);

// Lets count all messages
$num = mysql_num_rows($query);

// Lets set how many messages we want to display
$per_page = "10";

// Now we must calculate the last page
$last_page = ceil($num/$per_page);

// And set the first page
$first_page = "1";

// Here we are making the "First page" link
echo "<a href='?page=".$first_page."'>First page</a> ";

// If page is 1 then remove link from "Previous" word
if($page == $first_page){
    
    echo "Previous ";
    
}else{
    
    if(!isset($page)){
        
        echo "Previous ";
        
    }else{
        
        // But if page is set and it's not 1.. Lets add link to previous word to take us back by one page
        $previous = $page-1;
        echo "<a href='?page=".$previous."'>Previous</a> ";
    
    }
    
}

// If the page is last page.. lets remove "Next" link
if($page == $last_page){
    
    echo "Next ";    
    
}else{
    
    // If page is not set or it is set and it's not the last page.. lets add link to this word so we can go to the next page
    if(!isset($page)){
        
        $next = $first_page+1;
        echo "<a href='?page=".$next."'>Next</a> ";
        
    }else{
    
        $next = $page+1;
        echo "<a href='?page=".$next."'>Next</a> ";
    
    }
    
}

// And now lets add the "Last page" link
echo "<a href='?page=".$last_page."'>Last page</a>";

// Math.. It gets us the start number of message that will be displayed
$start = ($page-1)*$per_page;

// Now lets set the limit for our query
$limit = "LIMIT $start, $per_page";

// It's time for getting our messages
$sql = "SELECT * FROM messages $limit";
$query = mysql_query($sql);

echo "<br /><br />";

// And lets display our messages
while($row = mysql_fetch_array($query) or die(mysql_error())){
    
    echo $row['message']."<br />";
    
}

?>

I hope it helped you a little

Regards,
Jaan

[debtboy]

Good Tutorial +rep

[Jaan]

Thank you

[WingedPanther]

Very nice. +rep

[Jordan]

Very handy! +rep

[John]

Epic failure. (just kidding, but in all seriousness)

// Now lets get all messages from your database 
$sql = "SELECT * FROM messages"; 
$query = mysql_query($sql); 

// Lets count all messages 
$num = mysql_num_rows($query); 

Jordan did this and crippled the CodeCall server.

$num = mysql_query("SELECT COUNT(*) FROM messages"); 

is the preferred method of counting the rows in a database.

[amrosama]

nice tutorial +rep
@john: is theres a performance difference between these 2:
-"select count(`some_field_name`) from table"
-"select count(*) from table"

[John]

nice tutorial +rep
@john: is theres a performance difference between these 2:
-"select count(`some_field_name`) from table"
-"select count(*) from table"

Yes assuming the MyISAM engine is being used (and not Innodb - MyISAM is default) COUNT(*) will have the best performance. MyISAM caches the table row number so COUNT(*) is instantaneous. COUNT(`col`) could cause MySQL to perform a table scan depending on the column attributes.

[Jordan]

Epic failure. (just kidding, but in all seriousness)

// Now lets get all messages from your database 
$sql = "SELECT * FROM messages"; 
$query = mysql_query($sql); 

// Lets count all messages 
$num = mysql_num_rows($query); 

Jordan did this and crippled the CodeCall server.

$num = mysql_query("SELECT COUNT(*) FROM messages"); 

is the preferred method of counting the rows in a database.

I believe, if we look hard enough, we can find a flaw in everyone's tutorial. I looked over some of your tutorials from the past they also have errors.

nice tutorial +rep
@john: is theres a performance difference between these 2:
-"select count(`some_field_name`) from table"
-"select count(*) from table"

Check this out: COUNT(*) vs COUNT(col) | MySQL Performance Blog

Good performance information there.

[Jaan]

Well.. What can I say..
both ways work.. so..