如何使用$stmt->fetch(PDO::FETCH_ASSOC）;时输出数据 - How to output data when using $stmt->fetch(PDO::FETCH_ASSOC);

How to output data when using $stmt->fetch(PDO::FETCH_ASSOC);

使用$stmt->fetch(PDO::FETCH_ASSOC)时如何正确输出数据？现在我在做时得到一个单词作为我的结果

"select name, author, title from d_books"
// Other PDO stuff goes here
$arr = $stmt->fetch(PDO::FETCH_ASSOC);
foreach ($arr as $titleData) {
   echo $titleData['name'];
}

 $pdo = new PDO(/*Your credentials*/);
 $sql = `select name, author, title from d_books`
 $stmt = $pdo->prepare($sql);
 $stmt->execute(); 
 while ($arr = $stmt->fetch(PDO::FETCH_ASSOC)) {
    echo $arr['name'];
 }

或

 $pdo = new PDO(/*Your credentials*/);
 $sql = `select name, author, title from d_books`
 $stmt = $pdo->prepare($sql);
 $stmt->execute(); 
 $arr = $stmt->fetchAll(PDO::FETCH_ASSOC);
 foreach ($arr as $titleData) {
    echo $titleData['name'];
 }

在运行没有任何参数的查询时，您始终可以使用pdo->query()方法，这更快，但我认为这种情况不会发生太多（运行没有任何参数的查询）。