MySQL更新不更新某些行

Here is my double-minded query:

这是我的双头疑问:

$Quest = "SELECT * FROM TOAWorkorders";
 $FindTechResult = mysql_query($Quest, $cxn)
        or die ('The easter bunny is watching you' . mysql_error());

while ($row = mysql_fetch_array($FindTechResult))
 {          
      if (strpos($BBT, 0, 3) != 'Sys')
        {

              $IdNum = $row['IdNum'];

              $BBT = $row['BBT'];       
              $BBTArray = explode("-", $BBT);
              $TechNum = $BBTArray["0"];
              $Title = $BBTArray["2"];

             $Name = explode(" ", $BBTArray['1']);
             $FirstName = $Name["0"];
             $LastName = $Name["1"];

                }

echo $TechNum . ' !! ' . $FirstName . ' !! ' . $LastName . ' !! ' . $Title . '<br>';


$Quest = "UPDATE TOAWorkorders SET TechNum = '$TechNum', FirstName = '$FirstName', LastName = '$LastName', Title = '$Title' WHERE IdNum = '$IdNum'";
$result = mysql_query($Quest, $cxn)  or die(mysql_error());   
     }
$