//บรรทัดข้างล่างคือค้นหาโดยไม่มีวันที่เป็น keyword
if($lday=="" && $lmonth=="" && $lyear=="" && $nday=="" && $nmonth=="" &&$nyear==""){
if($goods!=""&&$company!=""){
$sql="select * from buy where goods like '%".$goods."%' and company like '%".$company."%'";
}elseif($goods!=""&&$company==""){
$sql="select * from buy where goods like '%".$goods."%'";
}elseif($goods==""&&$company!=""){
$sql="select * from buy where company like'%".$company."%'";
}else{
$sql="select * from buy";
}
if($goods!=""&&$company!=""){
$sql="select * from buy where goods like '%".$goods."%' and company like '%".$company."%' and date>= '$l' and date<='$n'";
}elseif($goods!=""&&$company==""){
$sql="select * from buy where goods like '%".$goods."%' and date>= '$l' and date<='$n'";
}elseif($goods==""&&$company!=""){
$sql="select * from buy where company like'%".$company."%' and date>= '$l' and date<='$n'";
}elseif($goods==""&&$company==""){
$sql="select * from buy where date>= '$l' and date<='$n'";