MySql ต่างกับ sql server

<?php
$database = 'yii2advanced';
 
try {
    $dbh = new PDO(
        'mysql:host=localhost;dbname=' . $database,
        'root',
        ''
    );
} catch (PDOException $e) {
    exit('Error!: ' . $e->getMessage());
}
$dbh->query('SET NAMES utf8');
 
switch ($_GET['op']) {
    case 'columns':{
            $table = $_GET['table'];
 
            $sql = "SELECT `COLUMN_NAME` AS name
    ,`DATA_TYPE` AS type
    ,IFNULL(`CHARACTER_MAXIMUM_LENGTH`, 0) AS maxlength
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_name = '" . $table . "';";
            $sth = $dbh->prepare($sql);
            $sth->execute();
            $results = [];
            if ($sth->rowCount() > 0) {
                while ($row = $sth->fetch(PDO::FETCH_ASSOC)) {
                    array_push($results, $row);
                }
                echo json_encode($results, JSON_NUMERIC_CHECK);
            }
        }break;
    case 'tables':{
            $sql = 'SHOW TABLES IN ' . $database . ';';
            $sth = $dbh->prepare($sql);
            $sth->execute();
            $results = [];
            if ($sth->rowCount() > 0) {
                while ($row = $sth->fetch(PDO::FETCH_COLUMN)) {
                    array_push($results, $row);
                }
            }
            echo json_encode($results);
        }break;
}

<?php
$database = 'TPA';
 
try {
    $dbh = new PDO(
        'sqlsrv:Server=MAGI\SQLEXPRESS;Database=' . $database
    );
} catch (PDOException $e) {
    exit('Error!: ' . $e->getMessage());
}
$dbh->query('SET CHARACTER_SET utf8_unicode_ci');
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
 
switch ($_GET['op']) {
    case 'columns':{
            $table = $_GET['table'];
 
            $sql = "SELECT [COLUMN_NAME] AS name
    ,[DATA_TYPE] AS type
    ,ISNULL([CHARACTER_MAXIMUM_LENGTH], 0) AS maxlength
FROM TPA.INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = '" . $table . "';";
            $sth = $dbh->prepare($sql, [PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL]);
            $sth->execute();
            $results = [];
            if ($sth->rowCount() > 0) {
                while ($row = $sth->fetch(PDO::FETCH_ASSOC)) {
                    array_push($results, $row);
                }
                echo json_encode($results, JSON_NUMERIC_CHECK);
            }
        }break;
    case 'tables':{
            $sql = 'SELECT [TABLE_NAME] FROM ' . $database . '.INFORMATION_SCHEMA.Tables;';
            $sth = $dbh->prepare($sql, [PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL]);
            $sth->execute();
            $results = [];
            if ($sth->rowCount() > 0) {
                while ($row = $sth->fetch(PDO::FETCH_COLUMN)) {
                    array_push($results, $row);
                }
                echo json_encode($results);
            }
        }break;
}