Connect to Multiple Databases using MySQLi

Question

I need to connect to two databases using PHP and use the results from the first query to get the rest of the data I need out of a second database.

So for the second c

Answer 1

You would need to make 2 different connections

<?php
    $mysqliDB1 = new mysqli('localhost', 'DB1UserId', 'pwd', 'db1');

    $mysqliDB2 = new mysqli('localhost', 'DB2UserId', 'pwd', 'db2');

Now when you use the $mysqliDB1->.... you are talking to the DB1 database and when you use the $mysqliDB2->.... you are talking to the DB2 database

So

$client = $mysqliDB1->query("SELECT client FROM appointments WHERE ID = $results")
         ->fetch_object();

$locn = $mysqliDB2->query("SELECT state,zipcode 
                           FROM location 
                           WHERE ClientID = {$client->FirstName}")
                  ->fetch_object();
echo $locn->state;
echo $locn->zipcode;

I am guessing the table name and so on, but I am not clarevoyant so you will have to fill that in for yourself.

Answer 2

If you want to perform queries in two databases at the same time you need to have two separate mysqli objects. To open the connection you can use the following code:

// Don't forget to enable error reporting!
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);

$db1 = new mysqli('localhost', 'user', 'pass', 'dbName');
$db1->set_charset('utf8mb4'); // always set the charset

$db2 = new mysqli('localhost', 'user', 'pass', 'dbName2');
$db2->set_charset('utf8mb4'); // always set the charset

Then you can perform your two statements in each database separately.

// get id value
$id = intval($_GET['cd']);

// Get client name from DB1
$stmt = $db1->prepare('SELECT client FROM appointments WHERE ID = ?');
$stmt->bind_param('s', $id);
$stmt->execute();
$client = $stmt->get_result()->fetch_object();

// Get state and zipcode from DB2
$stmt = $db2->prepare('SELECT state,zipcode FROM location WHERE ClientName  = ?');
$stmt->bind_param('s', $client->client);
$stmt->execute();
$location = $stmt->get_result()->fetch_object();

echo $location->state;
echo $location->zipcode;

Answer 3

This isn't tested, but I think it would go something like this.

<?php

$dbc1 = new MySQLi()or die('error connecting to database');
$dbc2 = new MySQLi()or die('error connecting to database');



//build query 1
$query1 = "SELECT * FROM Table";

$result1 = $dbc1->query($query) or die("Error in query");
$thing1 = '';
// check result
if($result1->num_rows){
    //fetch result as object
    $row = $result1->fetch_object();

    //set attributes
    $thing1 = $row->Name;
}   


//build query 2
$query2 = "SELECT * FROM AnotherTable WHERE Id = '$thing1'";

$result2 = $dbc2->query($query) or die("Error in query");
$thing2 = '';
// check result
if($result2->num_rows){
    //fetch result as object
    $row = $result2->fetch_object();

    //set attributes
    $thing2 = $row->Name;
}

?>