[英]Select the most recent 5 rows based on date
I haven't touched PHP in a while and trying to select the 5 most recent entries in my database and print them to screen. 我有一段时间没有触及PHP,并尝试在我的数据库中选择5个最新的条目并将它们打印到屏幕上。
I see mysql command isn't recommended anymore and to use PDO->mysql instead. 我不推荐使用mysql命令,而是使用PDO-> mysql。
My query is something like this: 我的查询是这样的:
SELECT id,title,date,author FROM table ORDER BY date DESC LIMIT 5;
I'm assuming I would have to put the values into an array and create a loop and output the results. 我假设我必须将值放入数组并创建一个循环并输出结果。
<?php
$db = new PDO('mysql:dbhost='.$dbhost.';dbname='.$dbname, $user, $pass);
while () {
print($title[$i], $date[$i], $author[$i]);
$i++
}
$db = null;
?>
I'm stuck filling in the gaps with the above code. 我用上面的代码填补了空白。
Update: The $db = new PDO.... line is reporting an error message: 更新:$ db = new PDO ....行报告错误消息:
PHP Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[HY000] Can't connect to local MySQL server through socket... in /var/...
PDO is confirmed to be installed and enabled. 确认已安装并启用PDO。 My other web apps on the server can connect to the same remote mysql server fine.
我在服务器上的其他Web应用程序可以很好地连接到同一个远程mysql服务器。
<?php
$host = 'localhost'; $db = 'db-name'; $user = 'db-user'; $pw = 'db-password';
$conn = new PDO('mysql:host='.$host.';dbname='.$db.';charset=utf8', $user, $pw);
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
?>
<?php
$sql = "SELECT id,title,date,author FROM table ORDER BY date DESC LIMIT 5";
$query = $conn->prepare($sql);
$query->execute();
$row = $query->fetch(PDO::FETCH_ASSOC);
$totalRows = $query->rowCount();
?>
<?php do {
// print your results here ex: next line
echo 'Title: '.$row['title'].' Date: '.$row['date'].' Author: '.$row['author'].'<br>';
} while ($row = $query->fetch(PDO::FETCH_ASSOC)); ?>
Happy Coding ! 快乐的编码!
Don't forget to close and release resources 不要忘记关闭并释放资源
<?php $query->closeCursor(); ?>
EDIT 编辑
I recommend not echoing error messages once you have confirmed your code functions as expected; 一旦您按预期确认了代码功能,我建议不要回显错误消息; however if you want to simply use plain text you can do this...
但是,如果你想简单地使用纯文本,你可以这样做......
You can add this to your connection block... 您可以将其添加到您的连接块...
if ($conn->connect_error) {
die("Database Connection Failed");
exit;
}
You can also change your query block... 您还可以更改查询块...
try {
$sql = "SELECT id,title,date,author FROM table ORDER BY date DESC LIMIT 5";
$query = $conn->prepare($sql);
$query->execute();
$row = $query->fetch(PDO::FETCH_ASSOC);
$totalRows = $query->rowCount();
} catch (PDOException $e) {
die("Could not get the data you requested");
exit;
}
Again, it is recommended that errors not be echoed. 同样,建议不要回显错误。 Use error checking only for debugging.
仅将错误检查用于调试。
<?php
$db = PDO('mysql:dbhost=$dbhost;dbname=$dbname', $user, $pass);
$sth = $db->prepare("SELECT id,title,date,author FROM table ORDER BY date LIMIT 5");
$sth->execute();
$result = $sth->fetch(PDO::FETCH_ASSOC);
print_r($result);
?>
in a loop: 在循环中:
while($row = $sth->fetch()) {
echo $row['column'];
}
From the documentation: http://php.net/manual/en/pdostatement.fetch.php 来自文档: http : //php.net/manual/en/pdostatement.fetch.php
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