ใช้คำสั่งsum like อยากให้ช่วยadd code ให้หน่อยครับคือ ต้องการดึง filed valuetime จากtable oee มา sum เฉพาะ "tr"

<?php

$total=0;
$objConnect = odbc_connect("oee","","") or die("Error Connect to Database");
$sumtr ="SELECT  id,valuetime,item FROM oee where item LIKE 'tr%'"; //"SELECT  id,valuetime,item FROM oee where item LIKE 'tr%'";

$objExec = odbc_exec($objConnect, $sumtr) or die ("Error Execute [".$sumtr."]");    
$Num_Rows = 0;
while(odbc_fetch_row($objExec))$Num_Rows++; // Count Record
 
$Per_Page = 60;   // Per Page  //SELECT item , SUM(valuetime) As Sumtr FROM oee GROUP BY item HAVING SUM(item) = tr;

 
$Page = $_GET["Page"];
if(!$_GET["Page"])
{
    $Page=1;
}

$Prev_Page = $Page-1;
$Next_Page = $Page+1;
 
$Page_Start = (($Per_Page*$Page)-$Per_Page)+1;
if($Num_Rows<=$Per_Page)
{
$Num_Pages =1;
}
else if(($Num_Rows % $Per_Page)==0)
{
$Num_Pages =($Num_Rows/$Per_Page) ;
}
else
{
$Num_Pages =($Num_Rows/$Per_Page)+1;
$Num_Pages = (int)$Num_Pages;
}
$Page_End = $Per_Page * $Page;
?>
</p>
<table width="600" border="1">
<tr>
<th width="91"> <div align="center">item </div></th>

</tr>
<?
for($i=$Page_Start;$i<=$Page_End;$i++)
{
$objResult = odbc_fetch_array($objExec,$i);
?>

<tr>
<td><div align="center">
  <?=$objResult["valuetime"];?>
</div></td>

</tr>
<?
}
?>