使用PDO和关系数据库获取行 [英] Fetch row with pdo and relational database

问题描述

我有一个小问题，我有一个包含2个表，用户和注释的数据库，我需要使用pdo打印结果. 如果我尝试这段代码，一切都会很好:

i have a little problem, i have a database with 2 tables, users and comments and i need to print the result with pdo. if i try this code, everything works great:

$stmt = $dbConnection->prepare("SELECT comment_text, username FROM users, comments WHERE users.user_id = comments.user_id");
$stmt->execute();
$stmt->fetch(PDO::FETCH_ASSOC);

foreach ($stmt as $row) {
    echo $row['comment_text'] . "<br>By " . $row['username'] . "<br>";
}

但是，如果我尝试添加一个获取结果的变量，我得到的结果将完全不同，只有2​​行，并且只有值的第一个字母...

But if i try to add a variable which get the result of fetch i get a totally different result with only 2 rows and only the first letter of the value...

$stmt = $dbConnection->prepare("SELECT comment_text, username FROM users, comments WHERE users.user_id = comments.user_id");
$stmt->execute();
$comment = $stmt->fetch(PDO::FETCH_ASSOC);

foreach ($comment as $row) {
    echo $row['comment_text'] . "<br>By " . $row['username'] . "<br>";
}

推荐答案

如果我尝试这段代码，一切都会很好:

if i try this code, everything works great:

不是.
这样，您将失去第一个评论.所以应该就是

it is not.
this way you are losing the very first comment. So it should be just

$stmt->execute();
foreach($stmt as $row )
{
    echo $row['comment_text']."<br>By ".$row['username']."<br>" ;
}

如果要将结果保存到数组中，则必须为此使用适当的函数 :

in case you want to save the result in array, you have to use the appropriate function for that:

$stmt->execute();
$comments = $stmt->fetchAll(PDO::FETCH_ASSOC);
foreach($comments as $row )
{
    echo $row['comment_text']."<br>By ".$row['username']."<br>" ;
} 

fetch()仅获得一条记录，而fetchAll()则按照名称提示进行操作

while fetch() is getting you only one record, fetchAll() is doing what the name suggests

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