$sql6="SELECT * FROM select_seat WHERE `train_id` = '$train_id' AND `date` = '$train_date' AND `arrival` = '$train_arrival' AND `row` = '$i' AND `seat` = '$best_line'";
$sql6="SELECT * FROM select_seat WHERE `train_id` = '$train_id' AND `date` = '$train_date' AND `arrival` = '$train_arrival' AND `row` = '$i' AND `seat` = '$best_line'";