mysql connect multiple databases in single webpage using php

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.

In this instructional exercise, utilizing three PHP APIs (API – Application Programming Interface), we’ll associate two diverse MySQL databases on a solitary PHP page. The three APIs are-

PHP’s MySQL Extension for connect multiple databases

PHP’s mysqli Extension for connect multiple databases

PHP Data Objects(PDO) for connect multiple databases

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);