我有来自数据库的数据行,我想有一个带有简单分页的表,最简单的方法是什么?
如果有人可以提供,我会很高兴。
Answers:
这是HTML和代码的混合,但是它很基础,易于理解,并且解耦起来也很简单,可以满足您的需求。
try {
// Find out how many items are in the table
$total = $dbh->query('
SELECT
COUNT(*)
FROM
table
')->fetchColumn();
// How many items to list per page
$limit = 20;
// How many pages will there be
$pages = ceil($total / $limit);
// What page are we currently on?
$page = min($pages, filter_input(INPUT_GET, 'page', FILTER_VALIDATE_INT, array(
'options' => array(
'default' => 1,
'min_range' => 1,
),
)));
// Calculate the offset for the query
$offset = ($page - 1) * $limit;
// Some information to display to the user
$start = $offset + 1;
$end = min(($offset + $limit), $total);
// The "back" link
$prevlink = ($page > 1) ? '<a href="?page=1" title="First page">«</a> <a href="?page=' . ($page - 1) . '" title="Previous page">‹</a>' : '<span class="disabled">«</span> <span class="disabled">‹</span>';
// The "forward" link
$nextlink = ($page < $pages) ? '<a href="?page=' . ($page + 1) . '" title="Next page">›</a> <a href="?page=' . $pages . '" title="Last page">»</a>' : '<span class="disabled">›</span> <span class="disabled">»</span>';
// Display the paging information
echo '<div id="paging"><p>', $prevlink, ' Page ', $page, ' of ', $pages, ' pages, displaying ', $start, '-', $end, ' of ', $total, ' results ', $nextlink, ' </p></div>';
// Prepare the paged query
$stmt = $dbh->prepare('
SELECT
*
FROM
table
ORDER BY
name
LIMIT
:limit
OFFSET
:offset
');
// Bind the query params
$stmt->bindParam(':limit', $limit, PDO::PARAM_INT);
$stmt->bindParam(':offset', $offset, PDO::PARAM_INT);
$stmt->execute();
// Do we have any results?
if ($stmt->rowCount() > 0) {
// Define how we want to fetch the results
$stmt->setFetchMode(PDO::FETCH_ASSOC);
$iterator = new IteratorIterator($stmt);
// Display the results
foreach ($iterator as $row) {
echo '<p>', $row['name'], '</p>';
}
} else {
echo '<p>No results could be displayed.</p>';
}
} catch (Exception $e) {
echo '<p>', $e->getMessage(), '</p>';
}
$total == 0
之后COUNT(*)
是否避免所有不必要的逻辑(即仅向用户显示“未找到结果”,而不是构建用于分页的HTML等
count
FROM(SELECT ...)AS output
”来获取总数。
我发现一些容易理解的教程是:
将列表分成页面大小的块,并且一次只查询一个数据库,这更有意义。这大大减少了服务器处理时间和页面加载时间,并为您的用户提供了更小的信息摘要,因此他不会为您想喂他的东西而烦恼。这样做的行为称为分页。
一开始,基本的分页程序似乎很长且令人恐惧,但是一旦您闭上眼睛,深呼吸,分别看一下脚本的每个部分,您会发现它实际上很简单
剧本:
// find out how many rows are in the table
$sql = "SELECT COUNT(*) FROM numbers";
$result = mysql_query($sql, $conn) or trigger_error("SQL", E_USER_ERROR);
$r = mysql_fetch_row($result);
$numrows = $r[0];
// number of rows to show per page
$rowsperpage = 10;
// find out total pages
$totalpages = ceil($numrows / $rowsperpage);
// get the current page or set a default
if (isset($_GET['currentpage']) && is_numeric($_GET['currentpage'])) {
// cast var as int
$currentpage = (int) $_GET['currentpage'];
} else {
// default page num
$currentpage = 1;
} // end if
// if current page is greater than total pages...
if ($currentpage > $totalpages) {
// set current page to last page
$currentpage = $totalpages;
} // end if
// if current page is less than first page...
if ($currentpage < 1) {
// set current page to first page
$currentpage = 1;
} // end if
// the offset of the list, based on current page
$offset = ($currentpage - 1) * $rowsperpage;
// get the info from the db
$sql = "SELECT id, number FROM numbers LIMIT $offset, $rowsperpage";
$result = mysql_query($sql, $conn) or trigger_error("SQL", E_USER_ERROR);
// while there are rows to be fetched...
while ($list = mysql_fetch_assoc($result)) {
// echo data
echo $list['id'] . " : " . $list['number'] . "<br />";
} // end while
/****** build the pagination links ******/
// range of num links to show
$range = 3;
// if not on page 1, don't show back links
if ($currentpage > 1) {
// show << link to go back to page 1
echo " <a href='{$_SERVER['PHP_SELF']}?currentpage=1'><<</a> ";
// get previous page num
$prevpage = $currentpage - 1;
// show < link to go back to 1 page
echo " <a href='{$_SERVER['PHP_SELF']}?currentpage=$prevpage'><</a> ";
} // end if
// loop to show links to range of pages around current page
for ($x = ($currentpage - $range); $x < (($currentpage + $range) + 1); $x++) {
// if it's a valid page number...
if (($x > 0) && ($x <= $totalpages)) {
// if we're on current page...
if ($x == $currentpage) {
// 'highlight' it but don't make a link
echo " [<b>$x</b>] ";
// if not current page...
} else {
// make it a link
echo " <a href='{$_SERVER['PHP_SELF']}?currentpage=$x'>$x</a> ";
} // end else
} // end if
} // end for
// if not on last page, show forward and last page links
if ($currentpage != $totalpages) {
// get next page
$nextpage = $currentpage + 1;
// echo forward link for next page
echo " <a href='{$_SERVER['PHP_SELF']}?currentpage=$nextpage'>></a> ";
// echo forward link for lastpage
echo " <a href='{$_SERVER['PHP_SELF']}?currentpage=$totalpages'>>></a> ";
} // end if
/****** end build pagination links ******/
?>
本教程适用于希望使用户能够以可管理块的形式逐步遍历大量数据库行而不是一次性完成全部数据库行的开发人员。
<?php
// Custom PHP MySQL Pagination Tutorial and Script
// You have to put your mysql connection data and alter the SQL queries(both queries)
mysql_connect("DATABASE_Host_Here","DATABASE_Username_Here","DATABASE_Password_Here") or die (mysql_error());
mysql_select_db("DATABASE_Name_Here") or die (mysql_error());
////////////// QUERY THE MEMBER DATA INITIALLY LIKE YOU NORMALLY WOULD
$sql = mysql_query("SELECT id, firstname, country FROM myTable ORDER BY id ASC");
//////////////////////////////////// Pagination Logic ////////////////////////////////////////////////////////////////////////
$nr = mysql_num_rows($sql); // Get total of Num rows from the database query
if (isset($_GET['pn'])) { // Get pn from URL vars if it is present
$pn = preg_replace('#[^0-9]#i', '', $_GET['pn']); // filter everything but numbers for security(new)
//$pn = ereg_replace("[^0-9]", "", $_GET['pn']); // filter everything but numbers for security(deprecated)
} else { // If the pn URL variable is not present force it to be value of page number 1
$pn = 1;
}
//This is where we set how many database items to show on each page
$itemsPerPage = 10;
// Get the value of the last page in the pagination result set
$lastPage = ceil($nr / $itemsPerPage);
// Be sure URL variable $pn(page number) is no lower than page 1 and no higher than $lastpage
if ($pn < 1) { // If it is less than 1
$pn = 1; // force if to be 1
} else if ($pn > $lastPage) { // if it is greater than $lastpage
$pn = $lastPage; // force it to be $lastpage's value
}
// This creates the numbers to click in between the next and back buttons
// This section is explained well in the video that accompanies this script
$centerPages = "";
$sub1 = $pn - 1;
$sub2 = $pn - 2;
$add1 = $pn + 1;
$add2 = $pn + 2;
if ($pn == 1) {
$centerPages .= ' <span class="pagNumActive">' . $pn . '</span> ';
$centerPages .= ' <a href="' . $_SERVER['PHP_SELF'] . '?pn=' . $add1 . '">' . $add1 . '</a> ';
} else if ($pn == $lastPage) {
$centerPages .= ' <a href="' . $_SERVER['PHP_SELF'] . '?pn=' . $sub1 . '">' . $sub1 . '</a> ';
$centerPages .= ' <span class="pagNumActive">' . $pn . '</span> ';
} else if ($pn > 2 && $pn < ($lastPage - 1)) {
$centerPages .= ' <a href="' . $_SERVER['PHP_SELF'] . '?pn=' . $sub2 . '">' . $sub2 . '</a> ';
$centerPages .= ' <a href="' . $_SERVER['PHP_SELF'] . '?pn=' . $sub1 . '">' . $sub1 . '</a> ';
$centerPages .= ' <span class="pagNumActive">' . $pn . '</span> ';
$centerPages .= ' <a href="' . $_SERVER['PHP_SELF'] . '?pn=' . $add1 . '">' . $add1 . '</a> ';
$centerPages .= ' <a href="' . $_SERVER['PHP_SELF'] . '?pn=' . $add2 . '">' . $add2 . '</a> ';
} else if ($pn > 1 && $pn < $lastPage) {
$centerPages .= ' <a href="' . $_SERVER['PHP_SELF'] . '?pn=' . $sub1 . '">' . $sub1 . '</a> ';
$centerPages .= ' <span class="pagNumActive">' . $pn . '</span> ';
$centerPages .= ' <a href="' . $_SERVER['PHP_SELF'] . '?pn=' . $add1 . '">' . $add1 . '</a> ';
}
// This line sets the "LIMIT" range... the 2 values we place to choose a range of rows from database in our query
$limit = 'LIMIT ' .($pn - 1) * $itemsPerPage .',' .$itemsPerPage;
// Now we are going to run the same query as above but this time add $limit onto the end of the SQL syntax
// $sql2 is what we will use to fuel our while loop statement below
$sql2 = mysql_query("SELECT id, firstname, country FROM myTable ORDER BY id ASC $limit");
//////////////////////////////// END Pagination Logic ////////////////////////////////////////////////////////////////////////////////
///////////////////////////////////// Pagination Display Setup /////////////////////////////////////////////////////////////////////
$paginationDisplay = ""; // Initialize the pagination output variable
// This code runs only if the last page variable is ot equal to 1, if it is only 1 page we require no paginated links to display
if ($lastPage != "1"){
// This shows the user what page they are on, and the total number of pages
$paginationDisplay .= 'Page <strong>' . $pn . '</strong> of ' . $lastPage. ' ';
// If we are not on page 1 we can place the Back button
if ($pn != 1) {
$previous = $pn - 1;
$paginationDisplay .= ' <a href="' . $_SERVER['PHP_SELF'] . '?pn=' . $previous . '"> Back</a> ';
}
// Lay in the clickable numbers display here between the Back and Next links
$paginationDisplay .= '<span class="paginationNumbers">' . $centerPages . '</span>';
// If we are not on the very last page we can place the Next button
if ($pn != $lastPage) {
$nextPage = $pn + 1;
$paginationDisplay .= ' <a href="' . $_SERVER['PHP_SELF'] . '?pn=' . $nextPage . '"> Next</a> ';
}
}
///////////////////////////////////// END Pagination Display Setup ///////////////////////////////////////////////////////////////////////////
// Build the Output Section Here
$outputList = '';
while($row = mysql_fetch_array($sql2)){
$id = $row["id"];
$firstname = $row["firstname"];
$country = $row["country"];
$outputList .= '<h1>' . $firstname . '</h1><h2>' . $country . ' </h2><hr />';
} // close while loop
?>
<html>
<head>
<title>Simple Pagination</title>
</head>
<body>
<div style="margin-left:64px; margin-right:64px;">
<h2>Total Items: <?php echo $nr; ?></h2>
</div>
<div style="margin-left:58px; margin-right:58px; padding:6px; background-color:#FFF; border:#999 1px solid;"><?php echo $paginationDisplay; ?></div>
<div style="margin-left:64px; margin-right:64px;"><?php print "$outputList"; ?></div>
<div style="margin-left:58px; margin-right:58px; padding:6px; background-color:#FFF; border:#999 1px solid;"><?php echo $paginationDisplay; ?></div>
</body>
</html>