***MySQL if exist update else insert***
$result = mysql_query("update overall set name = '" . $name . "',latt = '" . $latt . "',logt = '" . $logt . "',address = '" . $address . "' WHERE name = '".$name."'");
if (mysql_affected_rows() == 0) {
$result = mysql_query("INSERT INTO overall(name,latt, logt,address,created_at) VALUES('$name','$latt', '$logt','$address',Now())");
}
แหล่งที่มาข้อมูล : forums.digitalpoint.com,Json send Data to Mysql IF mysql empty insert not update