PHP公告系统错误

Question

I want to make a simple announcements system where you just type announcements in a box and it can be viewed by others. I get this error when I submit the form:

Edit: Thanks, the php_announce.php now works, it does everything it's supposed to do, this is the new code :

<?php
// MySQL
$servername = "localhost";
$username = "testuser";
$password = "testpass";
$dbname = "testbase";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}
// Content
$content = $conn->real_escape_string($_POST['content']);
$query="INSERT INTO announcements (content) VALUES ('$content')";
$conn->query($query)
?>

Edit: Thanks for the help I fixed the code like this: after creating connection it does this:

$result=$conn->query("SELECT * FROM announcements");
#print_r($result);
while($row = $result->fetch_array(MYSQLI_ASSOC)){

echo $row['content']. " <br><br> ". "<b>Posted by: You</b>";
echo "<hr width=100%>";
}

Answer 1

In the first case, you need to provide a list of columns that correspond to the values you're trying to insert. e.g:

$query="INSERT INTO announcements (content) VALUES ('$content')";

Replace content with the name of the column in your table.

For the second one, the error message doesn't appear to correspond with the code you posted, but I'm guessing you forgot a semicolon on the preceding statement. Additionally, there's a missing ; in your last echo statement, although I'm not sure if that's what's causing the specific message you posted. Please repost the latest code from announce_out.php and I'll try to help.

There are some other issues with this approach in general. You're mixing mysqli and the older mysql, which is going to cause you additional errors. Instead of calling mysql_query(), you should be using $conn->query($query) so that you're actually using the connection you are establishing with new mysqli(). Additionally, to prevent injection attacks, you should escape your $content variable in this way:

$content = $conn->real_escape_string($_POST['content']);

This is a pretty basic way to escape strings and there are better methods like prepared statements that mysqli provides. I recommend checking out the page in the PHP manual: http://php.net/manual/en/mysqli.quickstart.php