从多个数据库执行多个语句

Question

数据库 1：

<?php
    $servername = "localhost";
    $dbname = "root";
    $dbpassword = "";
    $name = "one";

    $db_one = new mysqli($servername, $dbname, $dbpassword, $name);

    if ($db_one->connect_error) {
        die("We are likely experiencing a heavy traffic load, please come back later!");
    }
    ?>

数据库 2：

<?php
$servername = "localhost";
$dbname = "root";
$dbpassword = "";
$name = "two";

$db_one = new two($servername, $dbname, $dbpassword, $name);

if ($db_one->connect_error) {
    die("We are likely experiencing a heavy traffic load, please come back later!");
}
?>

我尝试的代码：

<?php require("db.php"); ?>

<?php //Select All Orders
$stmt = $db_one->prepare("SELECT * FROM `one`");
$stmt = $db_one->prepare("SELECT * FROM `one_table2`");
$stmt = $db_two->prepare("SELECT * FROM `two`");
$stmt->execute();

$result = $stmt->get_result();
if($result->num_rows > 0) {
  while($row = $result->fetch_assoc()) {

    echo $one[] = "<tr><td>".$row["fromdbone"]."</td>";
    echo $two[] = "<td>".$row["fromdbtwo"]."</td>";
    echo $three[] = "<td>".$row["fromdbone_table2"]."</td></tr>";
  }
}
$stmt->close();
?>

大家好，我在这里不知所措，我将如何从不同的表和数据库执行多个查询以便将它们全部放入一个表中？

非常感谢您的洞察力，我相信你们都比我聪明！

编辑：或者如果我要进行多重查询，我如何将它们全部放入一个 HTML 表中？

谢谢，我已经尝试了好几个小时，希望您能提供帮助！

Answer 1

由于两个数据库位于同一台服务器 (localhost) 上，因此您无需为它们使用不同的连接。使用单个连接，并连接所有表。可以使用数据库前缀访问不在默认数据库中的表。

$stmt = $db_one->prepare("SELECT * FROM one AS o
    JOIN one_table2 AS o2 ON o.id = o2.one_id
    JOIN two.two AS t ON o.id = t.one_id");
$stmt->execute();
$result = $stmt->get_result();
while ($row = $result->fetch_assoc()) {
    echo $one[] = "<tr><td>".$row["fromdbone"]."</td>";
    echo $two[] = "<td>".$row["fromdbtwo"]."</td>";
    echo $three[] = "<td>".$row["fromdbone_table2"]."</td></tr>";
  }
}
$stmt->close();

要多条语句，需要绑定参数。

$stmt1 = $db_one->prepare("SELECT * FROM `one`");
$stmt2 = $db_one->prepare("SELECT * FROM `one_table2` WHERE one_id = ?");
$stmt3 = $db_two->prepare("SELECT * FROM `two` WHERE one_id = ?");

$stmt2->bind_param("i", $one_id);
$stmt3->bind_param("i", $one_id);

$stmt1->execute();
$result1 = $stmt1->get_result();
while ($row1 = $result1->fetch_assoc();
    $one_id = $row['id'];
    $stmt2->execute();
    $result2 = $stmt2->get_result();
    $row2 = $result2->fetch_assoc();
    $stmt3->execute();
    $result3 = $stmt3->get_result();
    $row3 = $result3->fetch_assoc();
    echo $one[] = "<tr><td>".$row1["fromdbone"]."</td>";
    echo $two[] = "<td>".$row2["fromdbtwo"]."</td>";
    echo $three[] = "<td>".$row3["fromdbone_table2"]."</td></tr>";
}
$stmt1->close();
$stmt2->close();
$stmt3->close();