選擇多行的ID，並將其用於更新查詢中的WHERE IN子句

Question

已經嘗試了各種解決方案來解決我的問題，以從多個行中選擇ID，然后將其用於更新與這些ID匹配的特定行。

我目前已經部署了以下內容。 首先，對ID進行簡單的SELECT查詢，然后將其用於下一個UPDATE查詢中的WHERE子句：

$SelectTSubjectsQuery = "
SELECT subject_id FROM teachers_subjects
WHERE teacher_id = :teacher_id";

$statement = $pdo->prepare($SelectTSubjectsQuery);
$statement->bindParam(':teacher_id', $_SESSION['teacher_id']);
$statement->execute();

$FetchedTSubjects = Array();
$FetchedTSubjects = $statement->fetchAll();

現在是UPDATE查詢，它應該為與請求ID和先前選擇的subject_ID相匹配的對應行更新表中的Teacher_id和status_id：

$StatusUpdateQuery = "UPDATE requests_subjects SET teacher_id = :teacher_id, status_id = '2' WHERE request_id = :request_id AND requests_subjects.subject_id IN (".implode(',', $FetchedTSubjects).")";

$statement = $pdo->prepare($StatusUpdateQuery);
$statement->bindParam(':request_id', $_GET['id']);
$statement->bindParam(':teacher_id', $_SESSION['teacher_id']);
$statement->execute();

我的requests_subjects表應該更新，如下所示：

+---+-------------+------------+----------------+------------+
|id | request_id  | subject_id |   teacher_id   |  status_id |
+---+-------------+------------+----------------+------------+
| 1 |     19      |      1     |       0        |      1     |
| 2 |     19      |      2     |       0        |      1     |
| 2 |     19      |      3     |       0        |      1     |
| 2 |     20      |      1     |       4        |      3     |
| 2 |     21      |      1     |       5        |      3     |
+---+-------------+------------+----------------+------------+

因此，例如，如果Teacher_id ='2'且subject_ids為'2'和'3'的教師選擇了request_id ='19'的請求，則request_id ='19'且subject_ids為'2'和'的行3'應該用Teacher_id'2'和status_id ='2'更新。

編輯：哦，當然還有我當前得到的錯誤（顯然，它不適用於當前WHERE子句中的Array）：

Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[42S22]: Column not found: 1054 Unknown column 'Array' in 'where clause'' in /var/www/xxx/html/teacher.php:227 Stack trace: #0 /var/www/xxx/html/teacher.php(227): PDOStatement->execute() #1 {main} thrown in /var/www/xxx/html/teacher.php on line 227

我很感謝每一個建議。

Answer 1

我相信您無需在此處指定表名

requests_subjects.subject_id IN 

只需將其更改為

subject_id IN 

並嘗試一下。

Answer 2

問題是，您需要將數據正確地正確放置在數組中...

$SelectTSubjectsQuery = "SELECT subject_id FROM teachers_subjects WHERE teacher_id = :teacher_id";

$statement = $pdo->prepare($SelectTSubjectsQuery);
$statement->bindParam(':teacher_id', $_SESSION['teacher_id']);
$statement->execute();

$FetchedTSubjects = Array();
$FetchedTSubjects = $statement->fetchAll()

從代碼中，如果您print_r($FetchedTSubjects)將獲得以下結果或類似結果：

Array
(
    [0] => Array
        (
            [subject_id] => 1
            [0] => 1
        )

    [1] => Array
        (
            [subject_id] => 2
            [0] => 2
        )
)

如果嘗試內implode(',',$FetchedTSubjects) ，實際上是在嘗試將數組轉換為字符串，這就是

SQLSTATE[42S22]: Column not found: 1054 Unknown column 'Array' in 'where clause''

您需要執行以下操作：

$SelectTSubjectsQuery = "SELECT subject_id FROM teachers_subjects WHERE teacher_id = :teacher_id";

$statement = $pdo->prepare($SelectTSubjectsQuery);
$statement->bindParam(':teacher_id', $_SESSION['teacher_id']);
$statement->execute();

$FetchedTSubjects = Array();

// iterate all the rows to get the subject_id of each and put in an independent array
foreach($statement->fetchAll(\PDO::FETCH_ASSOC) as $subject) {
    array_push($FetchedTSubjects,$subject['subject_id']);
}

現在，如果您使用print_r($FetchedTSubjects) ，將獲得以下輸出：

Array
(
    [0] => 1
    [1] => 2
)

現在，您可以成功使用implode(',', $FetchedTSubjects) ，它會按預期返回（1,2）

注意： \\PDO::FETCH_ASSOC是PDOStatement::fetchAll和PDOStatement::fetch參數， 請檢查！

PDO :: FETCH_ASSOC：返回一個在結果集中返回的按列名索引的數組