' <--- in mysql text don't get inserted in database - php

Question

Hello i'm a beginner so please at least try to give me a hint,a example.
English isn't my main language so please endure it.
If somebody type " Hello my name is J'hon ' the text don't insert in database, but if he type 'Hello my name is jhon' it does. I think it is something about '
Ok so i'm having the problem that if someone types
'Hello my name is J[color=#FF0000]'[/color]hon J'onz. ' is not inserted in the database..
This is the script:
mysqli_query($DB_H, "INSERT INTO tickets (name, continutscurt, continut,type,status) VALUES ('".$_SESSION['username']."', '".$_POST['titlu']."', '".$_POST['continut']."', $numar, 0)");

Answer 1

You should really use prepared statements when dealing with any kind of user-input. If you for any weird reason isn't using prepared statements, take a look at the function mysqli::real_escape_string. This will deal with special characters, such as ', which may break the SQL.
With using prepared statements, your code would look like
if ($stmt = $DB_H->prepare("INSERT INTO tickets (`name`, continutscurt, continut, `type`, `status`) VALUES (?, ?, ?, ?, ?)")) {
$stmt->bind_param("ssssi", $_SESSION['username'], $_POST['titlu'], $_POST['continut'], $numar, 0);
$stmt->execute();
$stmt->close();
} else {
echo mysqli_error($DB_H);
}
If you however want to use mysqli::real_escape_string, you'll need to bind the SESSIONs and POSTs to a variable where in you insert instead, like this (you can also do it directly in the query, but this makes for cleaner code).
$username = mysqli_real_escape_string ($DB_H, $_SESSION['username']);
$titlu = mysqli_real_escape_string ($DB_H, $_POST['titlu']);
$continut = mysqli_real_escape_string ($DB_H, $_POST['continut']);
$numar = mysqli_real_escape_string ($DB_H, $numar);
if (!mysqli_query($DB_H, "INSERT INTO tickets (`name`, continutscurt, continut, `type`, `status`) VALUES ('$username', '$titlu', '$continut', '$numar', 0")) {
echo mysqli_error($DB_H);
}
I also put backticks ` around name, status and type, as these are keywords in SQL. This isn't strictly necessary, but it's good practice with words that are listed as either reserved words or keywords, more info on this list of keywords.
You shouldn't take for granted that your queries are successful, so I added an if-block around them. Errors shouldn't be displayed unless in production/development.
References:
http://php.net/manual/en/mysqli.real-escape-string.php
http://php.net/manual/en/mysqli.prepare.php
How can I prevent SQL injection in PHP?
https://dev.mysql.com/doc/refman/5.7/en/keywords.html

Answer 2

The issue is SQL Injection.
You have potentially unsafe values being included within the SQL text.
To see this, break up the code a little bit.
$sql = "INSERT INTO tickets ...'" . $val . "' ... ";
echo $sql;
The echo is there just as a way to see what's going on, for you to examine the contents of the string containing the SQL text. And then take that string over to another client, and test it. And you will see what the the problem is.
... VALUES ( ..., 'J'onz. ', ...
isn't valid. That single quote is ending the string, so the string is just 'J', and the next part, MySQL is going to try to interpret as part of the SQL, not the string value. (This is a nefarious vulnerability. Cleverly constructed strings and wreak havoc on your application and your database.)
One approach to fixing that is to sanitize the values, so they can be safely included.
... VALUES ( ..., 'J\'onz. ', ...
^^
... VALUES ( ..., 'J''onz. ', ...
^^
As a simple demonstration try these queries:
SELECT 'J\'onz. '
SELECT 'J''onz. '
SELECT 'J'onz. '
(The first two will return the string you expect, and the third will cause an error.)
The take away is that potentially unsafe values that are going to included in the text of a SQL statement need to be properly escaped. Fortunately, the MySQL client library includes mysqli_real_escape_string function. Variables that may potentially contain a single quote character can be run through that function, and the return from the function can be included in the SQL text.
$sql = "INSERT INTO tickets ...'"
. mysqli_real_escape_string($DB_H,$val)
. "' ... ";
Again, echo out the $sql and you can see that a single quote has been escaped, either by preceding it with a backslash character, or replacing it with two sinqle quotes.
There's a much better pattern than "escaping" strings. And that's to use prepared statements with bind placeholders.
The SQL text can be a static string:
$sql = 'INSERT INTO mytable (mycol) VALUES ( ? )'
And then you msyqli_prepare the statement.
And then supply values for the placeholders with a call to mysqli_bind_param.
And then call mysqli_execute.
With this pattern, we don't need to mess with running the "escape string" function to sanitize the inputs.