Mysql将数据插入double类型

I have problem with mysql, i have query like these

SELECT sum(Qty) AS Qty FROM sap_rekap_bc23 
INNER JOIN masterunit_sap ON masterunit_sap.unit = sap_rekap_bc23.Unit WHERE Qty>0 AND invno='T62TJ92013' 
GROUP BY HS_Code,HS_Desc,unit_tpb,Curr,Price,invno

And the result show up

Qty = 3144.6

But when i try insert to another table with my code (on PHP)

$qryuraian = "SELECT sum(Qty) AS Qty FROM sap_rekap_bc23
                          INNER JOIN masterunit_sap ON masterunit_sap.unit = sap_rekap_bc23.Unit
                          WHERE Qty>0 AND invno='T62TJ92013' GROUP BY HS_Code,HS_Desc,unit_tpb,Curr,Price,invno";

$listuraian = mysql_query($qryuraian,$conn);
while($item=mysql_fetch_array($listuraian))
                {
                    $inserttmp = "INSERT INTO tmp_sap_rekap_bc23 (Qty) 
                                  VALUES ('".$item['Qty']."')";

                    //mysql_query($inserttmp,$connweb);
                }

The Result my Qty on tmp_sap_rekap_bc23 show 3145. Why my data instant became rounded?? even tough my table tmp_sap_rekap_bc23 on field Qty was type Double??? Any ideas??

Found my problem!!. Is was my fault. I was set my field Qty on tmp_sap_rekap_bc23 length into 225 not 0. So i changed into 0. And viola is working back normal.