爲什麼此查詢創建看似隨機的結果？

Question

這對我來說沒有意義，但是這個查詢在部分內容中顯示了一些記錄，並且在一行中顯示了一些內容。看似沒有節奏或理性。更糟糕的是，當我在MySql中運行查詢時，它工作得很好，沒有任何問題。目前我認爲這是一個惡魔和/或超級惡魔。

$sql = "SELECT phonenumber,date,dataplan AS currentplan, SUM(datamb) AS value_sum FROM maindata2 WHERE email='".($_POST['email'])."' GROUP BY phonenumber,date"; 

$result = mysql_query($sql); 

$row = mysql_fetch_assoc($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 ($row["value_sum"],2) . "MB</td> "; 
    echo "<td>".($row['currentplan'] - ROUND ($row["value_sum"],2)) . "MB</td>"; 
    echo "<td>".$row['date'] . "</td></tr>"; 
} 
echo "</table>"; 

任何想法都會比我現在多一個！