Php question: capturing data in a form for mysql update

Question

I'm trying to update my database by building a form that
links a city with surrounding towns. I want to enter the main town
and the surrounding towns and then it updates all records that
contain the main town. the code runs without errors, but the data
i'm entering is not finding its way into the variables and doesn't
update the database . . . all help appreciated.
<form id="form1" name="form1" method="get"
action="demograph_updatep2.php">
<label><strong class="innerpageheading">Main
town</strong>
<input name="maintown" type="text" id="maintown" />
</label>
<p><label><span
class="results_13px">Nearby Town1</span>
<input name="nearbytown1" type="text" id="nearbytown1"
/>
</label>
</p>
<p>
<label><span
class="results_13px">NearbyTown2</span>
<input name="nearbytown2" type="text" id="nearbytown2"
/>
</label>
</p>
<p>
<label><span
class="results_13px">NearbyTown3</span>
<input name="nearbytown3" type="text" id="nearbytown3"
/>
</label>
</p>
<p>
<label><span
class="results_13px">NearbyTown4</span>
<input name="nearbytown4" type="text" id="nearbytown4"
/>
</label>
</p>
<p>
<label>
<input type="submit" name="Submit" value="Update" />
</label>
</p>
</form>
<?php
// setting variables
$maincity = $_GET['maintown'];
$nearbycity1 = $_GET['nearbytown1'];
$nearbycity2 = $_GET['nearbytown2'];
$nearbycity3 = $_GET['nearbytown3'];
$nearbycity4 = $_GET['nearbytown4'];
mysql_connect (localhost,"");
mysql_select_db("") or die( "Unable to select database");
mysql_query("UPDATE physician
SET
physician_City2 = $nearbycity1
WHERE physician_City1 IN ($maincity)
mysql_close();
?>
<?php
mysql_connect (localhost,"");
mysql_select_db("") or die( "Unable to select database");
mysql_query("UPDATE physician
SET
physician_City2 = 'East Grand Rapids'
WHERE physician_City1 IN ('Grand Rapids')
mysql_close();
?>

Answer 1

please ignore the last ten lines: ?>
<?php
mysql_connect (localhost,"");
mysql_select_db("") or die( "Unable to select database");
mysql_query("UPDATE physician
SET
physician_City2 = 'East Grand Rapids'
WHERE physician_City1 IN ('Grand Rapids')
mysql_close();
?>
i was using those to test the sql code