PHP paging principle example tutorial, PHP paging principle demonstration

//Connect to the database
$con = mysql_connect("localhost","root","");
mysql_select_db("xueshengchu",$con);
mysql_query("set names utf8 ");

$pageSize = 5; //Number of data items displayed on each page

$result = mysql_query("select * from stu_msg");
$totalNum = mysql_num_rows($result); //Total number of data items

$totalPageCount = intval($totalNum/$pageSize); //Total number of pages

//Determine which page the current page is
$nowPage = isset($_GET['page']) ? intval($_GET[' page']) : 1;
//Previous page
$prev = ($nowPage-1 //Next page
$next = ($nowPage+1 >= $totalPageCount) ? $totalPageCount : $nowPage+1;

//Offset
$offset = ($nowPage-1)*$pageSize;

/*You can get data, SQL statement paging principle
 * select * from table limit $offset,$size paging execution statement
*/ bbs.it-home.org
$sql = "select * from stu_msg limit $offset,$pageSize";
$result = mysql_query($sql, $con);
while($arr = mysql_fetch_array($result)){
 echo $arr['mid'].$arr['content']."";
}
echo "< ;a href="".$_SERVER['PHP_SELF']."?page=1">Homepage";
echo "Previous page";
echo "Next page";
echo "Last page< ;/a>";
?>

php paging code demonstration effect:

Code description: The php code above the png has been commented very clearly

Analysis:

1. The global variable $_SERVER['PHP_SELF'] is the absolute path to obtain script variables.

2. The essence of paging is to display the database data piece by piece. For example, in the above PHP example: Take out the first 5 items (first page): select * from table limit 0,5 Take out items 5 to 1 and 10 (second page): select * from table limit 5,5 This gives us the offset formula: $offset = ($nowPage-1)*$pageSize;

3. The intval() function is to get the integer value of the variable