Similar Queries different results, why? - php

Question

This one is a bit perplexing since it works perfectly on some records, and not on others. I am trying to pull all records with a specific email and only getting one record in about half of the cases. I have two query sets one pulling the data one is pulling it half of the time.
The first that works all the time is:
$tiera = mysql_query("SELECT SUM(datamb) AS tiera FROM maindata2 WHERE dataplan = '2' and email='".mysql_real_escape_string($_POST['email'])."'");
$tiera1 = mysql_fetch_assoc($tiera);
$tiera2 = $tiera1['tiera'];
$tieradata = mysql_query("SELECT SUM(dataplan) as datatotal FROM maindata2 WHERE dataplan = '2' and email='".mysql_real_escape_string($_POST['email'])."'");
$tieradata1 = mysql_fetch_assoc($tieradata);
$tieradata2 = $tieradata1['datatotal'];
echo "<table id='display1'>
<tr>
<th>Tier:</th>
<th>Total Data in Tier:</th>
<th>Data Usage This Period:</th>
<th>Remaining:</th>
</tr>";
echo "<tr>";
echo "<td>A</td> ";
echo "<td>". $tieradata2 . " MB</td> ";
echo "<td>". $tiera2. " MB</td> ";
echo "<td>".($tieradata1['datatotal'] - ROUND ($tiera1['tiera'],2)) . "MB</td></font> ";
echo "</table>";
I cant use this for my second query because I need it in the loop like this:
$sql = "SELECT phonenumber,date,email, dataplan AS currentplan, SUM(datamb) AS value_sum FROM maindata2 WHERE email='".mysql_real_escape_string($_POST['email'])."' GROUP BY dataplan, phonenumber ";
$result = mysql_query($sql);
if (!$result) {
echo "Could not successfully run query ($sql) from DB: " . mysql_error();
exit;
}
if (mysql_num_rows($result) == 0) {
echo "No Data Found For This Email";
exit;
}
$row = mysql_fetch_assoc($result);
$query = mysql_query($sql) or die(mysql_error());
$header_printed = false;
while($row = mysql_fetch_array($query)) {
if ($row['phonenumber']) {
if ($header_printed === false) {
echo "
<table id='display'>
<tr>
<th>Phone Number:</th>
<th>Data Plan:</th>
<th>Data Usage This Period:</th>
<th>Remaining:</th>
<th>Date Reporting:</th>
</tr>";
$header_printed = true;
}
while ($row = mysql_fetch_assoc($result)){
echo "<tr>";
echo "<td>".$row['phonenumber'] . "</td> ";
echo "<td>".$row['currentplan'] . "MB</td> ";
echo "<td>".ROUND ($row["value_sum"],2) . "MB</td> ";
echo "<td><font color=$color>".($row['currentplan'] - ROUND ($row["value_sum"],2)) . "MB</td></font> ";
echo "<td>".$row['date'] . "</td></tr>";
}
}
echo "</table>";
So the question is, what is missing from the second query that is in the first?