The CREATE DATABASE statement is used to create a MySQLi database. We must add the CREATE DATABASE statement to the mysqli_query() function to execute the command. 

Ex: (Create database)

<?php 
	$hostName = "localhost";
	$userName = "root";
	$pass = "";
	$database="mydatabase";

	// Create database  connection
	$con = new mysqli($hostName, $userName, $pass);

	// Check  database connection
	if ($con->connect_error) 
	{
	    die("Connection failed: " . $con->connect_error);
	} 

	$query = "CREATE DATABASE ".$database;
	if ($con->query($query) === TRUE) 
	{
	    echo "Database mydatabase created successfully";
	}
	else 
	{
	    echo "Sorry, database creation failed: " . $con->error;
	}
?>

Output:

Database mydatabase created successfully.

In the above example first, we create a connection with the database then we write a statement to create a database of name my database after that this statement is passed to mysqli_query() along with the connection variable of the database.