请参照以下代码:
<?php
//error_reporting(E_ALL);
//ini_set('display_errors', '1');
// 1. Create a database connection
$dbhost = "localhost";
$dbuser = "name";
$dbpass = "password";
$dbname = "widget_corp";
$connection = mysqli_connect($dbhost, $dbuser, $dbpass, $dbname);
// Test if connection succeeded
if(mysqli_connect_errno()) {
die("Database connection failed: " .
mysqli_connect_error() .
" (" . mysqli_connect_errno() . ")"
);
}
?>
<?php
// 2. Perform database query
$query = "SELECT * ";
$query .= "FROM subjects ";
$query .= "WHERE visible = 1 ";
$query .= "ORDER BY position ASC";
$result = mysqli_query($connection, $query);
// Test if there was a query error
if (!$result) {
die("Database query failed.");
}
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html lang="en">
<head>
<title>Databases</title>
</head>
<body>
<?php
while($row = mysqli_fetch_row($result))
{
echo "<pre>";
print_r($row);
echo "</pre>";
echo "<hr />";
}
?>
<?php
while($row = mysqli_fetch_assoc($result))
{
echo "<pre>";
print_r($row);
echo "</pre>";
echo "<hr />";
}
?>
<?php
// 4. Release returned data
mysqli_free_result($result);
?>
</body>
</html>
<?php
// 5. Close database connection
mysqli_close($connection);
?>
我希望返回的数据以不同的格式打印两次。
但是，当我运行程序时，只打印mysqli_fetch_row(不打印mysqli_fetch_assoc)。
你能解释一下为什么吗?
第一个循环一直到结果集的末尾，因此没有什么需要获取的了。您需要使用mysqli_data_seek()在循环之间重置指针(游标在结果集中的位置)。
的例子:
while($row = mysqli_fetch_row($result))
{
echo "<pre>";
print_r($row);
echo "</pre>";
echo "<hr />";
}
mysqli_data_seek($result, 0); // this resets the cursor to the first row
while($row = mysqli_fetch_assoc($result))
{
echo "<pre>";
print_r($row);
echo "</pre>";
echo "<hr />";
}
另外，请注意您不需要那么多<?php ... ?>块—您可以组合相邻的代码块。只要删除这些组合:
?>
<?php