Issue inserting data into a database - php

Question

I run this function and the value of the post form doesn't insert into the DB. I'm not getting any error messages but I checked and saw that $this->user_id is populating. Am I missing something else?
function senddata () {
$con = mysql_connect("localhost","root","XXXXX");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
mysql_select_db("user", $con);
$sql="INSERT INTO profile (collegemajor) VALUE('$_POST[major]') WHERE userid=$this->user_id";
mysql_close($con);
}

Answer 1

INSERT statement don't have WHERE clausule,
you need to send query!!!

Answer 2

First of all, I don't see the mysql_query() - the function to execute the query.
It seems like the problem is here:
$sql="INSERT INTO profile (collegemajor) VALUE('$_POST[major]') WHERE userid=$this->user_id";
Use $sql="INSERT INTO profile (collegemajor) VALUE('$_POST[major]'); instead.
The code:
function senddata () {
$con = mysql_connect("localhost","root","XXXXX");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
mysql_select_db("user", $con);
$sql="INSERT INTO profile (collegemajor) VALUE('$_POST[major]');";
mysql_query( $sql , $con );
mysql_close($con);
}

Answer 3

This should be an update function, it seems, rather than an insert function (if you're trying to update a row that already exists, which is seems you are based on the "Where" clause).
And, as others have mentioned, you never ran mysql_query() or similar function.