use mysqli_connect and mysql_select_db [duplicate]

Answer 1

Please, don't mix mysqli and mysql as they are different modules.

In your second code block you are using mysql_select_db and mysql_error, the first one requires mysql connection, not mysqli connection.

Answer 2

Replace Your Code:

$db_selected = mysqli_select_db("laboratory", $con); instead of

$db_selected = mysql_select_db("laboratory", $con);

Answer 3

The order of the parameters has been changed from:

mysql_select_db($Database, $Connection);

to:

mysqli_select_db($Connection, $Database);