Error in your SQL syntax

I have a problem in my Forum

Error message always when I write like I'm or don't it is the '

The error message is:

I wrote in the I'm test

PHP Code:

$a_name=$_POST['a_name'];

$a_email=$_POST['a_email'];

$a_answer=$_POST['a_answer']; 

$p=$_POST['p'];

$ip = $_SERVER['REMOTE_ADDR'];

// Insert answer 

mysql_query("UPDATE cat SET last=unix_timestamp() WHERE id='$cat'");

mysql_query("UPDATE forum_question SET lastuser='$signin_username' WHERE id='$id'");

$result2=mysql_query("INSERT INTO forum_answer(question_id, a_id, a_name, a_email, a_answer, a_datetime, ip)VALUES('$id', '$Max_id', '$a_name', '$a_email', '$a_answer', unix_timestamp(), '$ip')")or die (mysql_error());

PHP:

 

you have to use addslashes
for instance:
$a_answer= addslashes($_POST['a_answer']);

that should solve the ' problem.

Also don't forget to use stripslashes when you are showing the data

 

Thanks a lot that was it.