How to use Join in BD Query Laravel using two different databases? - php

Question

I got this piece of code bellow to show a table in a page, but it doesn't work. I got this error where says that the command was denied.
$posts = DB::connection('mysql2')
->table('wp_rocketsciencebrposts')
->join('users', 'users.rsbwordpressid', '=', 'wp_rocketsciencebrposts.post_author')
->select('ID', 'post_title', 'post_status', 'post_author', 'post_date', 'users.name')
->whereIn('post_status', ['publish', 'private'])
->where('post_type', 'post')
->orderBy('id', 'desc')
->paginate(15, ['*'], 'posts');
SQLSTATE[42000]: Syntax error or access violation: 1142 SELECT command
denied to user 'lovel095_heaven'#'177.134.6.23' for table 'users'
(SQL: select count(*) as aggregate from wp_rocketsciencebrposts
inner join mysql.users on users.rsbwordpressid =
mysql2.wp_rocketsciencebrposts.post_author where post_status
in (publish, private) and post_type = post)
Both databases are on the same server.
The table "wp_rocketsciencebrposts" comes from "lovel095_rocketsciencebr" database.
The table "users" comes from "lovel095_centralrsb" database.
In my .env file i git this:
DB_CONNECTION=mysql
DB_HOST=br862.hostgator.com.br
DB_PORT=3306
DB_DATABASE=lovel095_centralrsb
DB_USERNAME=(myusername)
DB_PASSWORD=(mypassword)
DB_CONNECTION_SECOND=mysql
DB_HOST_SECOND=br862.hostgator.com.br
DB_PORT_SECOND=3306
DB_DATABASE_SECOND=lovel095_rocketsciencebr
DB_USERNAME_SECOND=(myusername)
DB_PASSWORD_SECOND=(mypassword)
In my config>database.php file, i got this:
'mysql' => [
'driver' => 'mysql',
'url' => env('DATABASE_URL'),
'host' => env('DB_HOST', '127.0.0.1'),
'port' => env('DB_PORT', '3306'),
'database' => env('DB_DATABASE', 'forge'),
'username' => env('DB_USERNAME', 'forge'),
'password' => env('DB_PASSWORD', ''),
'unix_socket' => env('DB_SOCKET', ''),
'charset' => 'utf8mb4',
'collation' => 'utf8mb4_unicode_ci',
'prefix' => '',
'prefix_indexes' => true,
'strict' => true,
'engine' => null,
'options' => extension_loaded('pdo_mysql') ? array_filter([
PDO::MYSQL_ATTR_SSL_CA => env('MYSQL_ATTR_SSL_CA'),
]) : [],
],
'mysql2' => [
'driver' => env('DB_CONNECTION_SECOND'),
'host' => env('DB_HOST_SECOND'),
'port' => env('DB_PORT_SECOND'),
'database' => env('DB_DATABASE_SECOND'),
'username' => env('DB_USERNAME_SECOND'),
'password' => env('DB_PASSWORD_SECOND'),
],
Pls, help!

Answer 1

Most of database is not support a cross database join, I believe SQL server support it but it must be on the same server. Instead of forcing your application to joining two different database, just simply use the database separately.
In your case, simply select the posts first, then select the user name using foreach. Here's the workaround :
$posts = DB::connection('mysql2')
->table('wp_rocketsciencebrposts')
->select('ID', 'post_title', 'post_status', 'post_author', 'post_date')
->whereIn('post_status', ['publish', 'private'])
->where('post_type', 'post')
->orderBy('id', 'desc')
->paginate(15, ['*'], 'posts');
foreach ($posts as $key => $post){
$user = DB::connection('mysql')
->table('lovel095_centralrsb')
->where('id', $post->post_author)
->first();
$posts[$key]->post_author_name = $user->name;
}

Answer 2

Hello I'm not sure you need to configure 2 databases to execute that kind of query.
Just make sure the credentials you are using to connect to one database is able to access both, it works with MySql.
From here i suggest you read that other stackoverflow answer
Basically you need to prefix tables with database name for the join to work.
I suggest you first try this from PhpMyAdmin then translate into Laravel Query Builder.
Remember that you can use entire raw queries in the Query builder, like :
DB::select( DB::raw("SELECT * FROM some_table WHERE some_col = '$someVariable'") );