Why can't PHP connect to the database?

<code>$dbc = @mysqli_connect('localhost','root','lalala');
if(@mysqli_select_db("one",$dbc)){
    print 'YES!';
}else{
    print 'NO!';
    mysqli_error($dbc);
    exit();
}</code>

That’s it for a few lines of code. I can connect to mysql, but I can't connect to the database and there is no error message.
Using wamp’s phpmyadmin

Reply content:

<code>$dbc = @mysqli_connect('localhost','root','lalala');
if(@mysqli_select_db("one",$dbc)){
    print 'YES!';
}else{
    print 'NO!';
    mysqli_error($dbc);
    exit();
}</code>

That’s it for a few lines of code. I can connect to mysql, but I can't connect to the database and there is no error message.
Using wamp’s phpmyadmin

Function: mysqli_select_db(connection,dbname)

You have reversed the parameters.

You can check the manual. Mysql and mysqli are different.
bool mysqli_select_db (mysqli $link, string $dbname);
bool mysql_select_db (string $database_name [, resource $ link_identifier])
It should be said that it is just the opposite. Remember to put it when testing Turn on debug.

You try to connect to the database using the command line
mysql -u -p