問題描述

我有 3 個數據庫，現在我需要將每個數據庫中的多個表連接到單個查詢中.我該怎么做?

I have 3 databases, and now I need to join several tables from each one of them into a singel query. How do I do this?

這是我的連接:

try {
    $con_options = array(
        PDO::ATTR_EMULATE_PREPARES => false,
        PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
        PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES utf8',
        PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,  // _SILENT (pub) || _WARNING || _EXCEPTION  (dev)
    );

    $con_1 = new PDO('mysql:host=localhost; dbname=database_1', 'user_1', 'pass_1', $con_options);
    $con_2 = new PDO('mysql:host=localhost; dbname=database_2', 'user_2', 'pass_2', $con_options);
    $con_3 = new PDO('mysql:host=localhost; dbname=database_3', 'user_3', 'pass_3', $con_options);

} catch (PDOException $err) { 
    //  catch, record/log and do stuff with errors
}

我有 3 個不同的用戶，每個數據庫都有一個唯一的密碼.一個數據庫存儲 facebook-apps 和其他 iframe 應用程序的應用程序數據.另一個保存所有網上商店數據，如產品、訂單、客戶等，而第三個保存網站結構和內容.

I have 3 different users with a unique password for each database. One database stores application-data for facebook-apps and other iframe applications. Another one holds all webshop data like products, orders, customers etc. while the third one holds site structure and content.

現在；我想以某種方式在單個查詢中 JOIN 將它們三個放在一起.

Now; I would like to JOIN the three of them together in a single query somehow.

在我寫這個問題的時候；我的一個想法是讓另一個超級"用戶可以訪問所有三個數據庫，并且只執行常規的多表查詢?這是一個可以接受的解決方案嗎?

While I was writing this question; One idea I got was to have another "super"-user with access to all three databases and just do a regoular multi table query? Would that be an acceptable solution?

如果是這樣，我是否還必須在查詢中指定哪個數據庫?

If so, do I have to specify which database aswell in the query?

推薦答案

您需要一個可以訪問所有三個數據庫的用戶.

You will need a user that has access to all three databases.

您將通過指定完整的表名將它們連接在一起，如下所示:

You will JOIN them together by specifying full table name, something like this:

SELECT * FROM database_1.logs AS d1 LEFT JOIN database_2.users AS d2 
  ON d1.username = d2.username ORDER BY d1.timestamp DESC LIMIT 10

這篇關于php sql 將來自不同數據庫的多個表連接在一起的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！