php - 使用$stmt->fetch(PDO::FETCH_ASSOC)时如何输出数据；

Question

使用$stmt->fetch(PDO::FETCH_ASSOC)时如何正确输出数据？现在我在做的时候得到的结果是单个单词

"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'];
}

Answer 1

 $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'];
 }

在运行不带任何参数的查询时，您始终可以使用 pdo->query() 方法，这样速度更快，但我认为这种情况不会经常发生(运行不带任何参数的查询)。