php - 如何在mysqli中将一列添加到多个表中？

Question

首先我选择一个表来从 id 列中读取值

$db_hand1 = mysqli_connect($server, "root", "password",$database1);
$result = mysqli_query($db_hand1, "SELECT id FROM table");

现在我想将一列添加到另一个数据库的表中:

$db_hand2 = mysqli_connect($server, "root", "password",$database2);

while($row = mysqli_fetch_array($result)){
    $user_id= $row['id'];
    $result = mysqli_query($db_hand2,"ALTER TABLE $user_id ADD us_id INT( 1 ) NULL DEFAULT '1'");
}

但是这个while 不起作用。它总是在第一个表中添加一列。当我手动执行时:

$db_hand2 = mysqli_connect($server, "root", "password",$database2);
$user_id= "table_name";
$result = mysqli_query($db_hand2,"ALTER TABLE $user_id ADD us_id INT( 1 ) NULL DEFAULT '1'");

并手动设置 $user_id 作为它工作的表的名称。

Answer 1

你重写了$result，改变成

$db_hand2 = mysqli_connect($server, "root", "password",$database2);

    while($row = mysqli_fetch_array($result)){
        $user_id= $row['id'];
        $result_alter = mysqli_query($db_hand2,"ALTER TABLE $user_id ADD us_id INT( 1 ) NULL DEFAULT '1'");
    }