Insert where...?

[Jgreenday]

I'm trying to make a form update data in a table and having a problem with my MySQL knowlage
once a user logs in they have the option to update user data,
so the user name is stored using the $_session arrray,
so basicly

a user logs in with their username, then they goto a form and they can update their data, so i was trying somthing like this

$query = "insert into company where username = '$_SESSION[login]'
           (cname,ctype,dname,csize,cinfo,city,street,phone,email) values ('$cname', '$ctype', '$dname', '$csize', '$cinfo','$city','$street', '$phone','$email')";
   mysql_query($query) or 
             die (mysql_error()); 

$_SESSION[login] = where the username has been stored from the login page

Username = the feild that is being checked
Company = the database table

can anyone help out i'm getting the error:

You have an error in your SQL syntax. Check the manual that corresponds to your MySQL server version for the right syntax to use near 'where username = '' (cname,ctype,dname,csize,cinfo,c

[iceraider]

$query = "insert into company
                (cname,ctype,dname,csize,cinfo,city,street,phone,email) 
                values
('$cname', '$ctype', '$dname', '$csize', '$cinfo','$city','$street', '$phone','$email')  

                 where username = '$_SESSION[login]'"; 

[Lars_Berg]

Use the update statement to change data.

[Jgreenday]

could u give me an example using the code i posted?
i'm not very good with MySQL

[________]

$query = "UPDATE company
SET
cname = '$cname',
ctype = '$ctype',
dname = '$dname',
csize = '$csize',
cinfo = '$cinfo',
city = '$city',
street = '$street',
phone = '$phone',
email = '$email'
WHERE
username = '$_SESSION[login]'
";

If there are any fields that you don't want to update, skip them. Eg.: if you only want to update the email, use this query:
$query = "UPDATE company
SET
email = '$email'
WHERE
username = '$_SESSION[login]'
";