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Paging in PHP – PHP Paging Tutorial

PHP Paging & Automatic Pagination Tutorial - Paging made easy

I have written a php paging tutorial before. Admittedly, it wasn't the greatest. I don't think I was as clear as I wanted to be. SO I'm trying again. At the end of this tutorial, there is a file named php-automatic-pagination.php.txt
Please download it! It will help you understand the following.

Here is what we will be making..nice, simple pagers! (Dont worry about the Image #x text, thats really not part of the tutorial)

Paging in php and automatic pagination is something every coder has to deal with when coding in php. I mean, you COULD show all results on 1 page and skip the php paging, but paging is necessary to reduce bandwidth and organize content. Paging is very easy to do and I will walk you through it step by step.

PHP automatic paging comes with a few questions:
Paging 1 : Page Size - How many results would you like to display per page?
Paging 2 : How can we bring back proper results in mysql?
Paging 3 : How can we print a pager that will help show the next items.

Decide on your page size - 10, 15, 25, 50, 100. It really depends on what you would like to do. For this tutorial I will use 15.

//we want 15 results per page

$pgsize=15;

//if there is a p variable in the query string e.g: page.php?p=5 we will get this value, else we will use 1 (page 1)

$pg=(is_numeric($_GET["p"]) ? $_GET["p"] : 1);

//lets determine where we would like to get results from
//if $pg is 1, this calculation results in 0 (we want to start from the first record in the database)
//if $pg is 2, this calculation will result in 1*15..which means we will start at the 15th index of the database (row 16)

$start=($pg-1)*$pgsize;

//let us query the database for our results
//you will notice LIMIT and $start and $pgsize.
//On page 1, this query will be SELECT * FROM image_table LIMIT 0,15 - this means return 15 rows starting at row-index 0 (row 1)
//On page 2, this query will be SELECT * FROM image_table LIMIT 15, 15 - this means we will return 15 rows starting at row-index 15 (row 16)
//On page 3, this query will be SELECT * FROM image_table LIMIT 30,15 - this means we will return 15 rows starting at row-index 30 (row 31)
GET IT?!?!?!

$imgs=mysql_query("SELECT * FROM image_table LIMIT $start, $pgsize");

//we will also need the total number of records in our table
//notice there is no limit? we want to know how many records are in the entire table!
//we can use COUNT(*), COUNT(1), or COUNT(fieldname), they will all return the same result

$img_total=mysql_query("SELECT COUNT(1) FROM image_table");

//mysql_query returns a resource id, we can use this to get the row it has returned

$img_total=mysql_fetch_row($img_total);

//the count will be the first field in this row

$img_total=$img_total[0];

//lets determine how many pages we will need
//WRONG!, this will cut off results..why?
//say we have 31 images, and our page size is 15. 31/15= ~2.x...We need to round this result up!

$max_pages=$img_total / $pgsize;

//use this line instead

$max_pages=ceil($img_total/$pgsize);

Once we have all this information, we can use a handy little function I have written named printPager. This function will print out a neat little pager. It uses a helper function named add_querystring_var which was from Added Bytes here:
http://www.addedbytes.com/code/querystring-functions/

Copy/paste this function into your page or into one of your includes:
This will print out your awesome little pager!

PHP Automatic Pagination Function

Print Pager is called like so:

PHP Pager Styles

Download this tutorials script! It will help you understand. Right click: php-automatic-pagination-tutorial.php and click Save as. Then get rid of the .txt extension and name it php if you would like to run it. You will need to setup a database table to use for the tutorial. It can have an id field and another field.

If you enjoyed this post please leave a comment! I like reading and responding to all my readers!
Thanks

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