php – connect multiple databases databases in single webpage

mysql connect multiple databases in single webpage using php you will learn how to select the records from connect multiple databases tables using the SQL SELECT query in PHP.

1st database
database name :: onlinecode_db_one
table name :: user_table_one
+----+------------+-----------+-----------------------------+
| id | first_name | last_name | user_email                  | // column name
+-----------+------------+-----------+----------------------+
| 1  | Peter      | Kong      | peterKong@mail.com          |
| 2  | John       | smith     | johnsmith@mail.com          |
| 3  | Shuvo      | Kent      | Shuvokent@mail.com          |
| 4  | nick       | Habib     | nickHabib@mail.com          |
| 5  | Anthony    | Potter    | Anthonypott@mail.com        |
+-----------+------------+-----------+----------------------+

2st database
database name :: onlinecode_db_two
table name :: user_table_two
+----+------------+-----------+-----------------------------+
| id | first_name | last_name | user_email                  | // column name
+-----------+------------+-----------+----------------------+
| 1  | Peter      | Kent      | peterKong@mail.com          |
| 2  | John       | Habib     | johnsmith@mail.com          |
| 3  | Shuvo      | Kong      | Shuvokent@mail.com          |
| 4  | max        | smith     | johnHabib@mail.com          |
| 5  | Anthony    | Potter    | Anthonypott@mail.com        |
+-----------+------------+-----------+----------------------+

$database_host = 'localhost'; // database host name
// if using port then add port $database_host = 'localhost:3036'; 
$database_user = 'database_user'; // database user name
$database_pass = 'database_password_one'; // database user password
$database_name = 'onlinecode_db_one';  // database name

// connect with database
$database_conn_one = mysql_connect($database_host, $database_user, $database_pass);

// check database connection
if(! $database_conn_one )
{
    // error in database connection
    die('Could not connect to database : ' . mysql_error());
}



$database_host = 'localhost'; // database host name
// if using port then add port $database_host = 'localhost:3036'; 
$database_user = 'database_user'; // database user name
$database_pass = 'database_password_two'; // database user password
$database_name = 'onlinecode_db_two';  // database name

// connect with database
$database_conn_two = mysql_connect($database_host, $database_user, $database_pass);

// check database connection
if(! $database_conn_two )
{
    // error in database connection
    die('Could not connect to database : ' . mysql_error());
}

// select query form 1st data base "onlinecode_db_one"
$sql_select_query_one = 'SELECT id,first_name,last_name,user_email FROM user_table';

mysql_select_db($database_name_one);
$sql_result_one = mysql_query( $sql_select_query_one, $database_conn_one );
if(! $sql_result_one )
{
    // error in sql query or Fetch data
    die('Could not get data: ' . mysql_error());
}
while($result = mysql_fetch_array($sql_result_one, MYSQL_ASSOC))
{
    echo "User ID :{$result['id']}".
      "First Name : {$result['first_name']}".
      "Last Name : {$result['last_name']}".
      "Email Address : {$result['user_email']}";
}
echo "Get data successfully";

// close connection with Mysql database
mysql_close($database_conn_one);


// select query form 2st data base "onlinecode_db_two"
$sql_select_query_two = 'SELECT id,first_name,last_name,user_email FROM user_table';

mysql_select_db($database_name_two);
$sql_result_two = mysql_query( $sql_select_query_two, $database_conn_two );
if(! $sql_result_two )
{
    // error in sql query or Fetch data
    die('Could not get data: ' . mysql_error());
}
while($result = mysql_fetch_array($sql_result_two, MYSQL_ASSOC))
{
    echo "User ID :{$result['id']}".
      "First Name : {$result['first_name']}".
      "Last Name : {$result['last_name']}".
      "Email Address : {$result['user_email']}";
}
echo "Get data successfully";

// close connection with Mysql database
mysql_close($database_conn_two);