Question

我遇到了从两个不同的表中检索值的问题。到目前为止，这是代码：

$result = mysqli_query($conn,"SELECT * FROM articles");
$num = mysqli_num_rows($result);

while ($row = mysqli_fetch_array($result)) {
    $uid=$row['_uid'];

    $result2 = mysqli_query($conn, "SELECT _username FROM users WHERE _id = '$uid' ";
    $num2 = mysqli_num_rows($result2);

    while ($row2 = mysqli_fetch_array($result2)) {
        $username = $row2['_username'];
    }
    $divtext='<h3>'.$row['_posttype'].'</h3> <h2>'.$username.' </h2>';
}

我一直在阅读，我应该在一段时间内对多个查询执行此操作，在w3上也发现，您可以使用以下命令直接将值直接分配给变量：

"SELECT _username INTO $username FROM users WHERE  _id = '$uid'  LIMIT 1";

但这在myadmin内部的SQL中有效，在php中我找不到如何强制转换它。我还用fetch_row替换了fetch_assoc，仍然一无所有，为此我已经挣扎了两天。

Answer 1

您可以使用单个查询选择所有值

SELECT a._uid , a._posttype, u._username 
FROM articles a
INNER JOIN users u on a._uid = u._id

..

$result = mysqli_query($conn,
  "SELECT a._uid , a._posttype, u._username 
  FROM articles a
  INNER JOIN users u on a._uid = u._id");
$num = mysqli_num_rows($result);

while ($row = mysqli_fetch_array($result)) {

    $divtext='<h3>'.$row['_posttype'].'</h3> <h2>'.$username.' </h2>';

}  

$echo $divtext;

使用php从while循环语句中的不同表中获取值

1 个答案: