我似乎無法找到的PHP/SQL錯誤

Question

執行時，它總是聲明「此時停車托架不可用」，即使數據庫中有其他說明。我究竟做錯了什麼？可能還有其他錯誤，但我似乎無法通過這一個。

$db = connect(); 
try { 
    $db->beginTransaction(); 
    if(isWeekend($bookingDate)){ 
     $stmt = $db->prepare('SELECT bayid FROM parkbay p WHERE p.bayid=:bayID AND EXISTS (SELECT * FROM parkbay p WHERE p.bayid=:bayID AND(:parktime BETWEEN avail_wend_start AND avail_wend_end) AND (:parktime+:duration BETWEEN avail_wend_start AND avail_wend_end))'); 
    } else { 
     $stmt = $db->prepare('SELECT bayid FROM parkbay p WHERE p.bayid=:bayID AND EXISTS (SELECT * FROM parkbay p WHERE p.bayid=:bayID AND(:parktime BETWEEN avail_wk_start AND avail_wk_end) AND (:parktime+:duration BETWEEN avail_wk_start AND avail_wk_end))'); 
    } 
    $stmt->bindValue(':bayID', $bayID, PDO::PARAM_INT); 
    $stmt->bindValue(':parktime', $bookingHour, PDO::PARAM_INT); 
    $stmt->bindValue(':duration', $duration, PDO::PARAM_INT); 
    $stmt->execute(); 
    $result = $stmt->fetch(); 
    $stmt->closeCursor(); 
    if (!empty($result)) {    
     $stmt2 = $db->prepare("SELECT * FROM booking b JOIN parkbay p ON (p.bayid=b.bayid) WHERE b.bayid=:bayID2 AND b.bookingdate=:bookingDate2 AND (:parktime2 BETWEEN b.bookinghour AND b.bookinghour + b.duration) AND (:parktime2 + :duration2 BETWEEN b.bookinghour AND b.bookinghour + b.duration)"); 
     $stmt2->bindValue(':bayID2', $bayID, PDO::PARAM_INT); 
     $stmt2->bindValue(':bookingDate2', $bookingDate, PDO::PARAM_STR); 
     $stmt2->bindValue(':parktime2', $bookingHour, PDO::PARAM_INT); 
     $stmt2->bindValue(':duration2', $duration, PDO::PARAM_INT); 
     $stmt2->execute(); 
     $result = $stmt2->fetchAll(); 
     $stmt2->closeCursor(); 
     if (empty($result)) {     
      $stmt3 = $db->prepare("SELECT c.name, t.width, t.height, t.length FROM cartype t JOIN car c ON (c.make = t.make AND c.model = t.model) WHERE c.name=:carname AND EXISTS (
SELECT p.site, p.length, p.width, p.height FROM parkbay p WHERE p.bayid=:bayID3 AND t.width<=p.width AND t.length<=p.length AND t.height<=p.height)"); 
      $stmt3->bindValue(':bayID3', $bayID, PDO::PARAM_INT); 
      $stmt3->bindValue(':carname', $car, PDO::PARAM_STR); 
      $stmt3->execute(); 
      $result = $stmt3->fetch(); 
      $stmt3->closeCursor(); 
      if (!empty($result)) { 
       $stmt4 = $db->prepare('INSERT INTO booking (bookingid, bayid, bookingdate, bookinghour, duration, memberno, car) VAlUES (DEFAULT, :bayIDBooking, :bookingDateBooking, :bookingHourBooking, :durationBooking, :memberNoBooking, :carBooking) RETURNING bookingid'); 
       $stmt4->bindValue(':bayIDBooking',$bayID,PDO::PARAM_INT); 
       $stmt4->bindValue(':bookingDateBooking',$bookingDate,PDO::PARAM_STR); 
       $stmt4->bindValue(':bookingHourBooking',$bookingHour,PDO::PARAM_INT); 
       $stmt4->bindValue(':durationBooking',$duration,PDO::PARAM_INT); 
       $stmt4->bindValue(':memberNoBooking',$memberNo,PDO::PARAM_INT); 
       $stmt4->bindValue(':carBooking',$car,PDO::PARAM_STR); 
       $stmt4->execute(); 
       $bookingID = $stmt4->fetchColumn(); 
       $stmt4->closeCursor(); 
       if ($stmt->execute()) { 
        $db->commit(); 
        $stmt5 = $db->prepare('SELECT b.*, (p.hourly_rate * b.duration) as cost FROM booking b JOIN member m ON (b.memberno = m.memberno) JOIN membershipplan p ON (m.plan = p.title) WHERE b.bookingid=:bookingID'); 
      $stmt5->bindValue(':bookingID',$bookingID,PDO::PARAM_INT); 
        $stmt5->execute(); 
        if ($stmt->execute()) { 
         $results = $stmt5->fetch(); 
         $stmt5->closeCursor(); 
         $results['status']='success'; 
         return $results; 
        }else{ //STMT 5 - confirm Booking Insert and Cost - Fail 
         $db->rollback(); 
         $results['status']=' Error making booking and getting cost. Check that membership plan is set.'; 
         return $results; 
        } 
       }else{ //STMT 4 - Insert Booking Data - Fail 
        $db->rollback(); 
        $results['status']='Error making booking.'; 
        return $results; 
       } 
      } else { //STMT 3 - Check Car Dimensions - Fail 
       $db->rollback(); 
       $results['status']='Your car is too big for this parking bay.'; 
       return $results; 
      }     
     } else { //STMT 2 - Check Existing Bookings - Fail 
      $db->rollback(); 
      $results['status']='A booking already exists at this time.'; 
      return $results; 
     }     
    } else { //STMT 1 - Check Parking Availability - Fail 
     $db->rollback(); 
     $results['status']='This parking bay is not available at this time.'; 
     return $results; 
    } 
} catch (PDOException $e) { 
    print "Error submitting query to databse: " . $e->getMessage(); 
; 
} 
} 

其中：

function isWeekend($bookingDate) { 
return (date('N', strtotime($bookingDate)) >= 6); 

Answer 1

編輯過程的解釋

不要怕向下票;他們不是個人的。他們在那裏，因爲觀衆沒有看到自己試圖解決問題的證據。

由於您是新用戶SO，這裏有一些故障排除提示：

作爲基本原則，找出錯誤所在，打破它到它的基礎件。在你的情況下，看看是什麼驅動那個特定的錯誤。在這種情況下，這是因爲這一行if (!empty($result))。你指示它打印該消息如果這個不是的情況;它來自您的else聲明。這意味着$result爲空。如果它不是空的，你需要弄清楚爲什麼。

在這個特定的實例中，您似乎沒有在查詢中執行任何類型的行計數，因此默認情況下它會顯示爲空。

你可以做這樣的事情（使用您的代碼示例）得到行數：

$row_count = $result->rowCount(); 

從文檔瀏覽：http://php.net/manual/en/pdostatement.rowcount.php：

使用PDO ::查詢（）來使用與您預期的SELECT語句相同的謂詞發出SELECT COUNT（*）語句，然後使用PDOStatement :: fetchColumn（）來檢索將返回的行數。然後您的應用程序可以執行正確的操作。