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Php 例如，如何从行中仅查询30个用户，然后在下一页继续查询？

php

Php 例如，如何从行中仅查询30个用户，然后在下一页继续查询？,php,mysqli,rows,Php,Mysqli,Rows,我只想在一页上查询有限的结果。 例如，查询将在第1页显示数据库中的30个用户，然后在第2页继续显示另外30个用户。例如，当您转到对话历史记录时，您必须单击“显示更多”以加载更多以前的消息 编辑： <?php $dbhost = ''; $dbuser = ''; $dbpass = ''; $conn = mysql_connect($dbhost, $dbuser, $dbpass); if(! $conn ) { die('Could not connect: ' . mysql_

我只想在一页上查询有限的结果。
例如，查询将在第1页显示数据库中的30个用户，然后在第2页继续显示另外30个用户。例如，当您转到对话历史记录时，您必须单击“显示更多”以加载更多以前的消息

编辑：

<?php
$dbhost = '';
$dbuser = '';
$dbpass = '';
$conn = mysql_connect($dbhost, $dbuser, $dbpass);
if(! $conn )
{
  die('Could not connect: ' . mysql_error());
}
$sql = "SELECT * FROM members ORDER BY username";

mysql_select_db('');
$retval = mysql_query( $sql, $conn );
if(! $retval )
{
  die('Could not get data: ' . mysql_error());
}
while($row = mysql_fetch_array($retval, MYSQL_ASSOC))
{
    if($row['picture'] == ""){
    echo "<img src='profile_pictures/public_icon.png' width='46' height='50'><br>";}else {
                                        echo " <img width='50' height='50' src='profile_pictures/".$row['picture']."' alt='Profile Pic'><br>";
                                }
    echo "<b>Email:</b> {$row['email']} <br> ";

      echo "<b>Username: </b>{$row['username']}  </p> ";
    echo "<hr class='hr' />";

} 
?>

您将需要两个页面：第一个页面从数据库获取数据，第二个页面显示已分页的数据。下一个示例使用数组，将代码复制粘贴到具有给定名称的文件中，打开浏览器，并在地址栏中键入“localhost/show5_first.php”：

show5_first.php


<?php
session_start();
$my_array = array( "aa","bb","cc","dd","ee","ff","gg","hh","ii","jj",
                   "kk","ll","mm","nn","oo","pp","qq","rr","ss","tt",
                   "uu","vv","ww","xx","yy","zz" );
$_SESSION["my_data"] = implode( "|",$my_array );
$_SESSION["index"] = 0; // DATA WILL BE SHOWN STARTING WITH ITEM ZERO.
?>
<html>
  <head>
    <title>Jose Manuel Abarca Rodriguez</title>
  </head>
  <body>
    <form method="post" action="show5_rest.php">
      Enter how many items do you want to see per page:
      <input type="text" name="how_many" value="5"/>
      <br/>
      <input type="submit" value="Show items paged"/>
    </form>
  </body>
</html>



<?php
session_start();
if ( IsSet( $_POST["how_many"] ) )
   $_SESSION["how_many"] = (int)$_POST["how_many"];
?>
<html>
  <head>
    <title>Jose Manuel Abarca Rodriguez</title>
  </head>
  <body>
    Paging elements from <?php echo $_SESSION["index"]; ?> to
    <?php echo $_SESSION["index"] + ($_SESSION["how_many"]-1); ?>
    <br/>
    <br/>
<?php
// SHOW ITEMS OF THIS PAGE.
$my_array = explode( "|",$_SESSION["my_data"] );
for ( $i = $_SESSION["index"]; $i < ( $_SESSION["index"] + $_SESSION["how_many"] ); $i++ )
  if ( $i < count( $my_array ) )
    echo $my_array[$i] . "<br/>";
?>
    <br/>
<?php
// INDEX POR THE NEXT PAGE.
$_SESSION["index"] = $_SESSION["index"] + $_SESSION["how_many"];
if ( $_SESSION["index"] < count( $my_array ) )
   echo "<form action='show5_rest.php'>" .
        "<input type='submit' value='Next page'/>" .
        "</form>";
?>
  </body>
</html>




何塞·曼努埃尔·阿巴卡·罗德里格斯
输入每页要查看的项目数：




show5_rest.php


<?php
session_start();
$my_array = array( "aa","bb","cc","dd","ee","ff","gg","hh","ii","jj",
                   "kk","ll","mm","nn","oo","pp","qq","rr","ss","tt",
                   "uu","vv","ww","xx","yy","zz" );
$_SESSION["my_data"] = implode( "|",$my_array );
$_SESSION["index"] = 0; // DATA WILL BE SHOWN STARTING WITH ITEM ZERO.
?>
<html>
  <head>
    <title>Jose Manuel Abarca Rodriguez</title>
  </head>
  <body>
    <form method="post" action="show5_rest.php">
      Enter how many items do you want to see per page:
      <input type="text" name="how_many" value="5"/>
      <br/>
      <input type="submit" value="Show items paged"/>
    </form>
  </body>
</html>



<?php
session_start();
if ( IsSet( $_POST["how_many"] ) )
   $_SESSION["how_many"] = (int)$_POST["how_many"];
?>
<html>
  <head>
    <title>Jose Manuel Abarca Rodriguez</title>
  </head>
  <body>
    Paging elements from <?php echo $_SESSION["index"]; ?> to
    <?php echo $_SESSION["index"] + ($_SESSION["how_many"]-1); ?>
    <br/>
    <br/>
<?php
// SHOW ITEMS OF THIS PAGE.
$my_array = explode( "|",$_SESSION["my_data"] );
for ( $i = $_SESSION["index"]; $i < ( $_SESSION["index"] + $_SESSION["how_many"] ); $i++ )
  if ( $i < count( $my_array ) )
    echo $my_array[$i] . "<br/>";
?>
    <br/>
<?php
// INDEX POR THE NEXT PAGE.
$_SESSION["index"] = $_SESSION["index"] + $_SESSION["how_many"];
if ( $_SESSION["index"] < count( $my_array ) )
   echo "<form action='show5_rest.php'>" .
        "<input type='submit' value='Next page'/>" .
        "</form>";
?>
  </body>
</html>




何塞·曼努埃尔·阿巴卡·罗德里格斯
将元素从分页到







让我们看看你到目前为止做了什么。看看极限和偏移。选择*从用户限制30偏移量0；给你第1页。选择*从用户限制30偏移30；给你第2页。诸如此类。这里有一个链接给你@dudeman-看起来我必须手动添加每30个…有很多关于分页的好教程。我不知道这个有多好，但可能是一个好的开始：