php mysql使用pdo验证表是否存在

Question

我有以下代码来查看表（基于用户选择）是否存在，但它给了我以下错误：

[21-Mar-2019 11:34:11 UTC] PHP 致命错误：未捕获的 PDOException： SQLSTATE [42S02]：未找到基表或视图：1146 表 'filecleaner.opened_2019-03-21' 不存在于 C:\inetpub\wwwroot\FileCleaner\consultas.php:126 堆栈跟踪： 0 C:\inetpub\wwwroot\FileCleaner\consultas.php(126)：PDOStatement->执行（数组） 1 {main} 在第 126 行的 C:\inetpub\wwwroot\FileCleaner\consultas.php 中抛出

                 $pdo = Database::connect();
                 $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
                $stmt = $pdo->prepare("SELECT * FROM filecleaner.`Opened_". $DataDeConsulta ."`");
                $stmt->execute([$DataDeConsulta]);
                $count = $stmt->fetchColumn();
                if ($count <= 0) {
                $DataDeConsultaError = 'There is no information on that date!';
                 $valid = false;
                }
                if (isset($valid)) {
                    $pdo = Database::connect();
                    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
                    $sql = "SELECT * FROM filecleaner.`Opened_". $DataDeConsulta ."`";
                    //session_start();
                    $_SESSION['DataDeConsulta'] = $DataDeConsulta;
                    $query_result=$pdo->query($sql);
                    foreach ($pdo->query($sql) as $row) {
                        echo '<tr>';
                        echo '<td>'. htmlentities($row['Emails']) . '</td>';
                        echo ' ';
                        echo '</td>';
                        echo '</tr>';
                    }
                    Database::disconnect();
                }

Answer 1

你可以使用这个select来查看mysql/mariadb中是否存在表：

SELECT * FROM information_schema.tables WHERE table_schema = 'you-database-name' AND table_name = 'your-table-name';

Answer 2

您是否尝试过使用这种 try-catch 语法？

/**
* Check if a table exists in the current database.
*
* @param PDO $pdo PDO instance connected to a database.
* @param string $table Table to search for.
* @return bool TRUE if table exists, FALSE if no table found.
*/
function tableExists($pdo, $table) {

// Try a select statement against the table
// Run it in try/catch in case PDO is in ERRMODE_EXCEPTION.
try {
    $result = $pdo->query("SELECT 1 FROM $table LIMIT 1");
} catch (Exception $e) {
    // We got an exception == table not found
    return FALSE;
}

// Result is either boolean FALSE (no table found) or PDOStatement Object (table found)
return $result !== FALSE;
}