mysqli num_rows嵌套查询

I'm updating a site from MySQL to MySQLi, using OOP.

For the most part things are going well, but this line is giving me divine trouble:

$pager_total = mysql_num_rows(mysql_query($MySQLctr,$MyDB));

I've tried

$pager_total = $MyDB->query($MySQLctr)->num_rows;
and
$pager_total = ($MyDB->query($MySQLctr))->num_rows;
and
$new_object = $MyDB->query($MySQLctr);
$pager_total = $new_object->num_rows;

but no avail.

Any thoughts?

OOP mysqli is very simple :) try this example

$DBH=new mysql('location of database','username','password','database');
$get=$DBH->prepare('SELECT COUNT(*) FROM table');//notice the count(*) in the query, it's not the same as mysql_num_row() but works in the same way
//prepare is also a more secure way of processing query, please look up the difference between prepare and query though.
//$DBH->prepare('SELECT * FROM table WHERE ID=2'); will not work.
$get->execute();//execute the above prepared statement
$get->bind_result($count);//get the result of the query, should be whatever COUNT(*) returns
$get->close();//don't forget to close your connection

The mysqli of mysql_num_row() is $query->num_rows().

I added a little bit extra to get you started with OOP mysqli :) Notice though that I didn't use $get->num_rows() but COUNT(*) instead for a more simple example. Here is another method you may be more familiar with:

$counter=$DBH->query('SELECT * FROM table');
echo$counter->num_rows();

Also see here for more examples.

Thank you for your help everyone. It turns out that the db connection was being closed prematurely by one of the included files. I've noticed, during this project where I'm transitioning the code from procedural MySql to OOP MySQLi that the db closures didn't affect the functionality of the site before, but definitely do once OOP MySqli is in place. I'm curious why.